index.xml

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    <title>TP&#39;s School Site</title>
    <link>https://web.cs.sunyit.edu/~pereztr/</link>
    <description>Recent content on TP&#39;s School Site</description>
    <generator>Hugo -- gohugo.io</generator>
    <language>en-us</language>
    <lastBuildDate>Tue, 26 Apr 2016 05:25:43 -0400</lastBuildDate>
    <atom:link href="https://web.cs.sunyit.edu/~pereztr/index.xml" rel="self" type="application/rss+xml" />
    
    <item>
      <title>Main</title>
      <link>https://web.cs.sunyit.edu/~pereztr/1/</link>
      <pubDate>Tue, 26 Apr 2016 05:25:43 -0400</pubDate>
      
      <guid>https://web.cs.sunyit.edu/~pereztr/1/</guid>
      <description>

&lt;h3 id=&#34;home:d680e8a854a7cbad6d490c445cba2eba&#34;&gt;Home&lt;/h3&gt;

&lt;h2 id=&#34;school-documention:d680e8a854a7cbad6d490c445cba2eba&#34;&gt;School Documention&lt;/h2&gt;

&lt;p&gt;Lorem ipsum&lt;/p&gt;
</description>
    </item>
    
    <item>
      <title>CS350</title>
      <link>https://web.cs.sunyit.edu/~pereztr/cs350/</link>
      <pubDate>Tue, 26 Apr 2016 16:46:45 -0400</pubDate>
      
      <guid>https://web.cs.sunyit.edu/~pereztr/cs350/</guid>
      <description>

&lt;h3 id=&#34;information-and-knowledge-management:d680e8a854a7cbad6d490c445cba2eba&#34;&gt;Information and Knowledge Management&lt;/h3&gt;

&lt;h1 id=&#34;cs350:d680e8a854a7cbad6d490c445cba2eba&#34;&gt;CS350&lt;/h1&gt;

&lt;p&gt;Lorem ipsum&lt;/p&gt;
</description>
    </item>
    
    <item>
      <title>Homework 2</title>
      <link>https://web.cs.sunyit.edu/~pereztr/cs350/hw2/</link>
      <pubDate>Tue, 26 Apr 2016 22:43:06 -0400</pubDate>
      
      <guid>https://web.cs.sunyit.edu/~pereztr/cs350/hw2/</guid>
      <description>

&lt;h4 id=&#34;3-19:d680e8a854a7cbad6d490c445cba2eba&#34;&gt;3.19&lt;/h4&gt;

&lt;p&gt;Consider a STUDENT relation in a UNIVERSITY database with the following attributes
(Name, Ssn, Local_phone, Address, Cell_phone, Age, Gpa). Note that the cell phone
may be from a different city and state (or province) from the local phone.
A possible tuple of the relation is shown below:
&lt;img src=&#34;https://web.cs.sunyit.edu/~pereztr/~pereztr/images/cs350hw2.png&#34; alt=&#34;text&#34; /&gt;&lt;/p&gt;

&lt;p&gt;&lt;strong&gt;a&lt;/strong&gt;. &lt;em&gt;Q&lt;/em&gt;: Identify the critical missing information from the Local_phone and Cell_phone attributes.
(Hint: How do you call someone who lives in a different state or province?)&lt;/p&gt;

&lt;p&gt;&lt;em&gt;A&lt;/em&gt;: The critical missing information is the country code and aarea code.&lt;/p&gt;

&lt;p&gt;&lt;strong&gt;b&lt;/strong&gt;. &lt;em&gt;Q&lt;/em&gt;: Would you store this additional information in the Local_phone and Cell_phone
attributes or add new attributes to the schema for STUDENT?&lt;/p&gt;

&lt;p&gt;&lt;em&gt;A&lt;/em&gt;: I would store this in the &lt;code&gt;Local_phone&lt;/code&gt; and &lt;code&gt;Cell_phone&lt;/code&gt; attribute.&lt;/p&gt;

&lt;p&gt;&lt;strong&gt;c&lt;/strong&gt;. &lt;em&gt;Q&lt;/em&gt;: Consider the Name attribute. What are the advantages and disadvantages of splitting
this field from one attribute into three attributes (first name, middle name, and last name)?&lt;/p&gt;

&lt;p&gt;&lt;em&gt;A&lt;/em&gt;: The advatages are that it would be easier to index and look up.
Better queries can also be created. The disadvantages are that if you
already have the name saved into one attribute it would take some time
to go through every row and split them up.&lt;/p&gt;

&lt;p&gt;&lt;strong&gt;d&lt;/strong&gt;. &lt;em&gt;Q&lt;/em&gt;: What general guide line would you recommend for deciding when to store information in a single attribute and when to split the information?&lt;/p&gt;

&lt;p&gt;&lt;em&gt;A&lt;/em&gt;:I would first think about if this information can be used to group certain rows.&lt;/p&gt;

&lt;p&gt;&lt;strong&gt;e&lt;/strong&gt;. &lt;em&gt;Q&lt;/em&gt;: Suppose the student can have between 0 and 5 phones.
Suggest two different designs that allow this type of information.&lt;/p&gt;

&lt;p&gt;&lt;em&gt;A&lt;/em&gt;: If you know the student can have multiple phone numbers you can have another table that relates to the student and it could have 0 or more.&lt;/p&gt;

&lt;hr /&gt;

&lt;h4 id=&#34;4-12:d680e8a854a7cbad6d490c445cba2eba&#34;&gt;4.12&lt;/h4&gt;

&lt;p&gt;Specify the following queries in SQL on the database schema of Figure 1.2.
&lt;img src=&#34;https://web.cs.sunyit.edu/~pereztr/~pereztr/images/cs350fig12.png&#34; alt=&#34;fig12&#34; /&gt;
&lt;em&gt;Figure 1.2&lt;/em&gt;&lt;/p&gt;

&lt;p&gt;&lt;strong&gt;a&lt;/strong&gt;. Retrieve the names of all senior students majoring in ‘CS’ (computer sci- ence).&lt;/p&gt;

&lt;pre&gt;&lt;code&gt;SELECT Name 
FROM STUDENT 
WHERE Class=4 
AND Major=&#39;CS&#39;;
&lt;/code&gt;&lt;/pre&gt;

&lt;p&gt;&lt;strong&gt;b&lt;/strong&gt;. Retrieve the names of all courses taught by Professor King in 2007 and 2008.&lt;/p&gt;

&lt;pre&gt;&lt;code&gt;SELECT COURSE.Course_name 
FROM COURSE, SECTION 
WHERE COURSE.Course_number=SECTION.Course_number 
AND Instructor=&#39;King&#39; 
AND (Year=&#39;07&#39; OR Year=&#39;08&#39;);
&lt;/code&gt;&lt;/pre&gt;

&lt;p&gt;&lt;strong&gt;c&lt;/strong&gt;. For each section taught by Professor King, retrieve the course number, semester, year, and number of students who took the section.&lt;/p&gt;

&lt;pre&gt;&lt;code&gt;SELECT SECTION.Course_number, SECTION.Semester, SECTION.Year, GRADE_REPORT.Student_number
FROM SECTION, GRADE_REPORT 
WHERE SECTION.Instructor=&#39;King&#39; 
AND GRADE_REPORT.Section_identifier=SECTION.Section_identifier;
&lt;/code&gt;&lt;/pre&gt;

&lt;p&gt;&lt;strong&gt;d&lt;/strong&gt;. Retrieve the name and transcript of each senior student (Class = 4) majoring in CS. A transcript includes course name, course number, credit hours, semester, year, and grade for each course completed by the student.&lt;/p&gt;

&lt;pre&gt;&lt;code&gt;SELECT STUDENT.Name , COURSE.Course_name, 
    COURSE.Course_number, COURSE.Credit_hours, 
    SECTION.Semester, SECTION.Year, GRADE_REPORT.Grade 
FROM STUDENT, COURSE, SECTION, GRADE_REPORT
WHERE STUDENT.Student_number=GRADE_REPORT.Student_number 
AND SECTION.Section_identifier=GRADE_REPORT.Section_identifier 
AND SECTION.Course_number=COURSE.Course_number;
&lt;/code&gt;&lt;/pre&gt;
</description>
    </item>
    
    <item>
      <title>Homework 4</title>
      <link>https://web.cs.sunyit.edu/~pereztr/cs350/hw4/</link>
      <pubDate>Wed, 27 Apr 2016 00:59:08 -0400</pubDate>
      
      <guid>https://web.cs.sunyit.edu/~pereztr/cs350/hw4/</guid>
      <description>

&lt;h4 id=&#34;5-6:d680e8a854a7cbad6d490c445cba2eba&#34;&gt;5.6&lt;/h4&gt;

&lt;p&gt;&lt;strong&gt;a&lt;/strong&gt;. Retrieve the names and major departments of all straight-A students (students who have a grade of A in all their courses).&lt;/p&gt;

&lt;pre&gt;&lt;code&gt;SELECT STUDENT.Name, STUDENT.Major 
FROM STUDENT 
WHERE NOT EXISTS (
    SELECT * FROM GRADE_REPORT 
    WHERE GRADE_REPORT.Student_number = STUDENT.Student_number 
    AND GRADE &amp;lt;&amp;gt; &amp;quot;A&amp;quot;
);
&lt;/code&gt;&lt;/pre&gt;

&lt;p&gt;&lt;strong&gt;b&lt;/strong&gt;. Retrieve the names and major departments of all students who do not have a grade of A in any of their courses.&lt;/p&gt;

&lt;pre&gt;&lt;code&gt;SELECT STUDENT.Name, STUDENT.Major 
FROM STUDENT 
WHERE NOT EXISTS (
    SELECT * FROM GRADE_REPORT 
    WHERE GRADE_REPORT.Student_number = STUDENT.Student_number 
    AND GRADE = &amp;quot;A&amp;quot;
);
&lt;/code&gt;&lt;/pre&gt;

&lt;hr /&gt;

&lt;h4 id=&#34;5-7:d680e8a854a7cbad6d490c445cba2eba&#34;&gt;5.7&lt;/h4&gt;

&lt;p&gt;&lt;strong&gt;a&lt;/strong&gt;. Retrieve the names of all employees who work in the department that has the employee with the highest salary among all employees.&lt;/p&gt;

&lt;pre&gt;&lt;code&gt;SELECT e.Fname, e.Lname, e.Dno, e.Salary
FROM Employee e
    LEFT JOIN employee b
        ON e.Dno = b.Dno AND e.Salary &amp;lt; b.Salary
WHERE b.Salary is NULL;
&lt;/code&gt;&lt;/pre&gt;

&lt;p&gt;&lt;strong&gt;b&lt;/strong&gt;. Retrieve the names of all employees whose supervisor’s supervisor has ‘888665555’ for Ssn.&lt;/p&gt;

&lt;pre&gt;&lt;code&gt;SELECT Employee.Fname, Employee.Lname 
FROM Employee 
WHERE superssn = &amp;quot;888665555&amp;quot;;
&lt;/code&gt;&lt;/pre&gt;
</description>
    </item>
    
    <item>
      <title>Homework 5</title>
      <link>https://web.cs.sunyit.edu/~pereztr/cs350/hw5/</link>
      <pubDate>Wed, 27 Apr 2016 03:10:56 -0400</pubDate>
      
      <guid>https://web.cs.sunyit.edu/~pereztr/cs350/hw5/</guid>
      <description>

&lt;h4 id=&#34;6-23:d680e8a854a7cbad6d490c445cba2eba&#34;&gt;6.23&lt;/h4&gt;

&lt;p&gt;Specify the following queries in relational algebra on the database schema in Exercise 3.17:
&lt;img src=&#34;https://web.cs.sunyit.edu/~pereztr/~pereztr/images/cs350hw5.png&#34; alt=&#34;ex317&#34; /&gt;&lt;/p&gt;

&lt;p&gt;&lt;strong&gt;a&lt;/strong&gt;. For the salesperson named ‘Jane Doe’, list the following information for all the cars she sold: Serial#, Manufacturer, Sale_price.&lt;/p&gt;

&lt;p&gt;&lt;strong&gt;b&lt;/strong&gt;. List the Serial# and Model of cars that have no options.&lt;/p&gt;

&lt;p&gt;&lt;strong&gt;c&lt;/strong&gt;. Consider the NATURAL JOIN operation between SALESPERSON and SALE. What is the meaning of a left outer join for these tables (do not change the order of relations)? Explain with an example.&lt;/p&gt;

&lt;p&gt;&lt;strong&gt;d&lt;/strong&gt;. Write a query in relational algebra involving selection and one set opera- tion and say in words what the query does.&lt;/p&gt;

&lt;hr /&gt;

&lt;h4 id=&#34;6-26:d680e8a854a7cbad6d490c445cba2eba&#34;&gt;6.26&lt;/h4&gt;

&lt;p&gt;Specify queries c, d, and f of Exercise 6.18 in both tuple and domain relational
calculus.&lt;/p&gt;
</description>
    </item>
    
    <item>
      <title>Homework 6</title>
      <link>https://web.cs.sunyit.edu/~pereztr/cs350/hw6/</link>
      <pubDate>Wed, 27 Apr 2016 03:57:13 -0400</pubDate>
      
      <guid>https://web.cs.sunyit.edu/~pereztr/cs350/hw6/</guid>
      <description>

&lt;h4 id=&#34;7-19:d680e8a854a7cbad6d490c445cba2eba&#34;&gt;7.19&lt;/h4&gt;

&lt;p&gt;Consider the ER diagram in Figure 7.20, which shows a simplified schema for an
airline reservations system. Extract from the ER diagram the requirements and
constraints that produced this schema. Try to be as precise as possible in your
requirements and constraints specification.
&lt;img src=&#34;https://web.cs.sunyit.edu/~pereztr/~pereztr/images/cs350fig720.png&#34; alt=&#34;fig710&#34; /&gt;&lt;/p&gt;

&lt;hr /&gt;

&lt;h4 id=&#34;8-29:d680e8a854a7cbad6d490c445cba2eba&#34;&gt;8.29&lt;/h4&gt;

&lt;p&gt;Consideran ONLINE_AUCTION database system in which members(buyers and sellers)
participate in the sale of items. The data requirements for this system are
summarized as follows:&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;&lt;p&gt;The online site has members, each of whom is identified by a unique member number
and is described by an e-mail address, name, password, home address, and phone number.&lt;/p&gt;&lt;/li&gt;

&lt;li&gt;&lt;p&gt;A member may be a buyer or a seller. A buyer has a shipping address recorded in the
database. A seller has a bank account number and routing number recorded in the
database.&lt;/p&gt;&lt;/li&gt;

&lt;li&gt;&lt;p&gt;Items are placed by a seller for sale and are identified by a unique item number
assigned by the system. Items are also described by an item title, a description,
starting bid price, bidding increment, the start date of the auction, and the end
date of the auction.&lt;/p&gt;&lt;/li&gt;

&lt;li&gt;&lt;p&gt;Items are also categorized based on a fixed classification hierarchy (for example,
a modem may be classified as COMPUTER→HARDWARE →MODEM).&lt;/p&gt;&lt;/li&gt;

&lt;li&gt;&lt;p&gt;Buyers make bids for items they are interested in. Bid price and time of bid is
recorded. The bidder at the end of the auction with the highest bid price is
declared the winner and a transaction between buyer and seller may then proceed.&lt;/p&gt;&lt;/li&gt;

&lt;li&gt;&lt;p&gt;The buyer and seller may record feedback regarding their completed transactions.
Feedback contains a rating of the other party participating in the transaction (1–10)
and a comment.&lt;/p&gt;&lt;/li&gt;
&lt;/ul&gt;

&lt;p&gt;Design an Enhanced Entity-Relationship diagram for the ONLINE_AUCTION database and build the design using a data modeling tool such as ERwin or Rational Rose.&lt;/p&gt;
</description>
    </item>
    
    <item>
      <title>Homework 8</title>
      <link>https://web.cs.sunyit.edu/~pereztr/cs350/hw8/</link>
      <pubDate>Wed, 27 Apr 2016 04:04:07 -0400</pubDate>
      
      <guid>https://web.cs.sunyit.edu/~pereztr/cs350/hw8/</guid>
      <description>

&lt;h4 id=&#34;17-41:d680e8a854a7cbad6d490c445cba2eba&#34;&gt;17.41&lt;/h4&gt;

&lt;p&gt;Write program code to access individual fields of records under each of the following
circumstances. For each case, state the assumptions you make con- cerning pointers,
separator characters, and so on. Determine the type of information needed in the file
header in order for your code to be general in each case.&lt;/p&gt;

&lt;p&gt;&lt;strong&gt;a&lt;/strong&gt;. Fixed-length records with unspanned blocking&lt;/p&gt;

&lt;p&gt;&lt;strong&gt;b&lt;/strong&gt;. Fixed-length records with spanned blocking&lt;/p&gt;

&lt;p&gt;&lt;strong&gt;c&lt;/strong&gt;. Variable-length records with variable-length fields and spanned blocking&lt;/p&gt;

&lt;p&gt;&lt;strong&gt;d&lt;/strong&gt;. Variable-length records with repeating groups and spanned blocking&lt;/p&gt;

&lt;p&gt;&lt;strong&gt;e&lt;/strong&gt;. Variable-length records with optional fields and spanned blocking&lt;/p&gt;

&lt;p&gt;&lt;strong&gt;f&lt;/strong&gt;. Variable-length records that allow all three cases in parts c, d, and e&lt;/p&gt;

&lt;hr /&gt;

&lt;h4 id=&#34;18-19:d680e8a854a7cbad6d490c445cba2eba&#34;&gt;18.19&lt;/h4&gt;

&lt;p&gt;A PARTS file with Part# as the key field includes records with the following Part#
values: 23, 65, 37, 60, 46, 92, 48, 71, 56, 59, 18, 21, 10, 74, 78, 15, 16, 20, 24,
28, 39, 43, 47, 50, 69, 75, 8, 49, 33, 38. Suppose that the search field values are
inserted in the given order in a B+-tree of order p = 4 and pleaf = 3; show how the
tree will expand and what the final tree will look like.&lt;/p&gt;
</description>
    </item>
    
    <item>
      <title>Mini Project</title>
      <link>https://web.cs.sunyit.edu/~pereztr/cs350/miniproject/</link>
      <pubDate>Tue, 26 Apr 2016 17:59:46 -0400</pubDate>
      
      <guid>https://web.cs.sunyit.edu/~pereztr/cs350/miniproject/</guid>
      <description>

&lt;h2 id=&#34;cyboard-queries:d680e8a854a7cbad6d490c445cba2eba&#34;&gt;Cyboard Queries&lt;/h2&gt;

&lt;p&gt;Here are the queries I used in my Cyboard project&lt;br /&gt;
Project is on &lt;a href=&#34;https://github.com/pereztr5/cyboard&#34;&gt;Github&lt;/a&gt;&lt;/p&gt;

&lt;h3 id=&#34;aggregation:d680e8a854a7cbad6d490c445cba2eba&#34;&gt;Aggregation&lt;/h3&gt;

&lt;h5 id=&#34;get-service-and-the-last-status-for-that-team:d680e8a854a7cbad6d490c445cba2eba&#34;&gt;Get service and the last status for that team&lt;/h5&gt;

&lt;p&gt;Query&lt;/p&gt;

&lt;pre&gt;&lt;code&gt;db.results.aggregate(
    {&amp;quot;$match&amp;quot;: {&amp;quot;type&amp;quot;: &amp;quot;Service&amp;quot;}},
    {&amp;quot;$group&amp;quot;: 
        {
            &amp;quot;_id&amp;quot;: {&amp;quot;type&amp;quot;: &amp;quot;$group&amp;quot;, &amp;quot;tnumber&amp;quot;: &amp;quot;$teamnumber&amp;quot;, &amp;quot;tname&amp;quot;: &amp;quot;$teamname&amp;quot;},
            &amp;quot;status&amp;quot;: {&amp;quot;$last&amp;quot;: &amp;quot;$details&amp;quot;}
        }
    },
    {&amp;quot;$group&amp;quot;: 
        {
            &amp;quot;_id&amp;quot;: &amp;quot;$_id.type&amp;quot;,
            &amp;quot;teams&amp;quot;: {&amp;quot;$addToSet&amp;quot;: {&amp;quot;teamnumber&amp;quot;: &amp;quot;$_id.teamnumber&amp;quot;, &amp;quot;teamname&amp;quot;: &amp;quot;$_id.tname&amp;quot;, &amp;quot;status&amp;quot;: &amp;quot;$status&amp;quot;}}
        }
    }
)
&lt;/code&gt;&lt;/pre&gt;

&lt;p&gt;Result&lt;/p&gt;

&lt;pre&gt;&lt;code&gt;[{
        &amp;quot;_id&amp;quot; : &amp;quot;WWW 80&amp;quot;,
        &amp;quot;teams&amp;quot; : [
                {
                        &amp;quot;teamname&amp;quot; : &amp;quot;team1&amp;quot;,
                        &amp;quot;status&amp;quot; : &amp;quot;Status: 2&amp;quot;
                },
                {
                        &amp;quot;teamname&amp;quot; : &amp;quot;team4&amp;quot;,
                        &amp;quot;status&amp;quot; : &amp;quot;Status: 2&amp;quot;
                },
                {
                        &amp;quot;teamname&amp;quot; : &amp;quot;team7&amp;quot;,
                        &amp;quot;status&amp;quot; : &amp;quot;Status: 2&amp;quot;
                },
                ...
        ]
}, {
        &amp;quot;_id&amp;quot; : &amp;quot;WWW SSH&amp;quot;,
        &amp;quot;teams&amp;quot; : [
                {
                        &amp;quot;teamname&amp;quot; : &amp;quot;team7&amp;quot;,
                        &amp;quot;status&amp;quot; : &amp;quot;Status: 2&amp;quot;
                },
                {
                        &amp;quot;teamname&amp;quot; : &amp;quot;team1&amp;quot;,
                        &amp;quot;status&amp;quot; : &amp;quot;Status: 2&amp;quot;
                },
                ...
        ]
},
...
}]
&lt;/code&gt;&lt;/pre&gt;

&lt;h5 id=&#34;same-as-above-except-there-is-no-nested-object:d680e8a854a7cbad6d490c445cba2eba&#34;&gt;Same as above except there is no nested object&lt;/h5&gt;

&lt;p&gt;NOTE: Sort doesn&amp;rsquo;t always sort for some reason in Go
Query&lt;/p&gt;

&lt;pre&gt;&lt;code&gt;db.results.aggregate(
    {&amp;quot;$match&amp;quot;: {&amp;quot;type&amp;quot;: &amp;quot;Service&amp;quot;}},
    {&amp;quot;$group&amp;quot;: 
        {
            &amp;quot;_id&amp;quot;: {&amp;quot;type&amp;quot;: &amp;quot;$group&amp;quot;, &amp;quot;tnumber&amp;quot;: &amp;quot;$teamnumber&amp;quot;, &amp;quot;tname&amp;quot;: &amp;quot;$teamname&amp;quot;},
            &amp;quot;status&amp;quot;: {&amp;quot;$last&amp;quot;: &amp;quot;$details&amp;quot;}}
        },
    {&amp;quot;$group&amp;quot;: 
        {
            &amp;quot;_id&amp;quot;: &amp;quot;$_id.type&amp;quot;,
            &amp;quot;teams&amp;quot;: {&amp;quot;$addToSet&amp;quot;: {&amp;quot;number&amp;quot;: &amp;quot;$_id.tnumber&amp;quot;, &amp;quot;name&amp;quot;: &amp;quot;$_id.tname&amp;quot;, &amp;quot;status&amp;quot;: &amp;quot;$status&amp;quot;}}
        }
    },
    {&amp;quot;$unwind&amp;quot;: &amp;quot;$teams&amp;quot;},
    {&amp;quot;$project&amp;quot;: {&amp;quot;_id&amp;quot;: 0, &amp;quot;group&amp;quot;: &amp;quot;$_id&amp;quot;, &amp;quot;tnum&amp;quot;: &amp;quot;$teams.number&amp;quot;, &amp;quot;tname&amp;quot;: &amp;quot;$teams.name&amp;quot;, &amp;quot;status&amp;quot;: &amp;quot;$teams.status&amp;quot;}},
    {&amp;quot;$sort&amp;quot;: {&amp;quot;tnum&amp;quot;: 1, &amp;quot;group&amp;quot;: 1}}
)
&lt;/code&gt;&lt;/pre&gt;

&lt;p&gt;Result&lt;/p&gt;

&lt;pre&gt;&lt;code&gt;{ &amp;quot;group&amp;quot; : &amp;quot;MAIL POP&amp;quot;, &amp;quot;tnum&amp;quot; : 1, &amp;quot;tname&amp;quot; : &amp;quot;team1&amp;quot;, &amp;quot;status&amp;quot; : &amp;quot;Status: 2&amp;quot; }
{ &amp;quot;group&amp;quot; : &amp;quot;MAIL POP&amp;quot;, &amp;quot;tnum&amp;quot; : 2, &amp;quot;tname&amp;quot; : &amp;quot;team2&amp;quot;, &amp;quot;status&amp;quot; : &amp;quot;Status: 2&amp;quot; }
{ &amp;quot;group&amp;quot; : &amp;quot;MAIL POP&amp;quot;, &amp;quot;tnum&amp;quot; : 3, &amp;quot;tname&amp;quot; : &amp;quot;team3&amp;quot;, &amp;quot;status&amp;quot; : &amp;quot;Status: 2&amp;quot; }
{ &amp;quot;group&amp;quot; : &amp;quot;MAIL POP&amp;quot;, &amp;quot;tnum&amp;quot; : 4, &amp;quot;tname&amp;quot; : &amp;quot;team4&amp;quot;, &amp;quot;status&amp;quot; : &amp;quot;Status: 2&amp;quot; }
{ &amp;quot;group&amp;quot; : &amp;quot;MAIL POP&amp;quot;, &amp;quot;tnum&amp;quot; : 5, &amp;quot;tname&amp;quot; : &amp;quot;team5&amp;quot;, &amp;quot;status&amp;quot; : &amp;quot;Status: 1&amp;quot; }
{ &amp;quot;group&amp;quot; : &amp;quot;MAIL POP&amp;quot;, &amp;quot;tnum&amp;quot; : 6, &amp;quot;tname&amp;quot; : &amp;quot;team6&amp;quot;, &amp;quot;status&amp;quot; : &amp;quot;Status: 2&amp;quot; }
{ &amp;quot;group&amp;quot; : &amp;quot;MAIL POP&amp;quot;, &amp;quot;tnum&amp;quot; : 7, &amp;quot;tname&amp;quot; : &amp;quot;team7&amp;quot;, &amp;quot;status&amp;quot; : &amp;quot;Status: 2&amp;quot; }
{ &amp;quot;group&amp;quot; : &amp;quot;MAIL POP&amp;quot;, &amp;quot;tnum&amp;quot; : 8, &amp;quot;tname&amp;quot; : &amp;quot;team8&amp;quot;, &amp;quot;status&amp;quot; : &amp;quot;Status: 0&amp;quot; }
{ &amp;quot;group&amp;quot; : &amp;quot;MAIL POP&amp;quot;, &amp;quot;tnum&amp;quot; : 9, &amp;quot;tname&amp;quot; : &amp;quot;team9&amp;quot;, &amp;quot;status&amp;quot; : &amp;quot;Status: 2&amp;quot; }
{ &amp;quot;group&amp;quot; : &amp;quot;MAIL POP&amp;quot;, &amp;quot;tnum&amp;quot; : 10, &amp;quot;tname&amp;quot; : &amp;quot;team10&amp;quot;, &amp;quot;status&amp;quot; : &amp;quot;Status: 2&amp;quot; }
{ &amp;quot;group&amp;quot; : &amp;quot;MAIL SMTP&amp;quot;, &amp;quot;tnum&amp;quot; : 1, &amp;quot;tname&amp;quot; : &amp;quot;team1&amp;quot;, &amp;quot;status&amp;quot; : &amp;quot;Status: 2&amp;quot; }
{ &amp;quot;group&amp;quot; : &amp;quot;MAIL SMTP&amp;quot;, &amp;quot;tnum&amp;quot; : 2, &amp;quot;tname&amp;quot; : &amp;quot;team2&amp;quot;, &amp;quot;status&amp;quot; : &amp;quot;Status: 2&amp;quot; }
{ &amp;quot;group&amp;quot; : &amp;quot;MAIL SMTP&amp;quot;, &amp;quot;tnum&amp;quot; : 3, &amp;quot;tname&amp;quot; : &amp;quot;team3&amp;quot;, &amp;quot;status&amp;quot; : &amp;quot;Status: 2&amp;quot; }
{ &amp;quot;group&amp;quot; : &amp;quot;MAIL SMTP&amp;quot;, &amp;quot;tnum&amp;quot; : 4, &amp;quot;tname&amp;quot; : &amp;quot;team4&amp;quot;, &amp;quot;status&amp;quot; : &amp;quot;Status: 2&amp;quot; }
{ &amp;quot;group&amp;quot; : &amp;quot;MAIL SMTP&amp;quot;, &amp;quot;tnum&amp;quot; : 5, &amp;quot;tname&amp;quot; : &amp;quot;team5&amp;quot;, &amp;quot;status&amp;quot; : &amp;quot;Status: 2&amp;quot; }
{ &amp;quot;group&amp;quot; : &amp;quot;MAIL SMTP&amp;quot;, &amp;quot;tnum&amp;quot; : 6, &amp;quot;tname&amp;quot; : &amp;quot;team6&amp;quot;, &amp;quot;status&amp;quot; : &amp;quot;Status: 0&amp;quot; }
{ &amp;quot;group&amp;quot; : &amp;quot;MAIL SMTP&amp;quot;, &amp;quot;tnum&amp;quot; : 7, &amp;quot;tname&amp;quot; : &amp;quot;team7&amp;quot;, &amp;quot;status&amp;quot; : &amp;quot;Status: 2&amp;quot; }
{ &amp;quot;group&amp;quot; : &amp;quot;MAIL SMTP&amp;quot;, &amp;quot;tnum&amp;quot; : 8, &amp;quot;tname&amp;quot; : &amp;quot;team8&amp;quot;, &amp;quot;status&amp;quot; : &amp;quot;Status: 2&amp;quot; }
{ &amp;quot;group&amp;quot; : &amp;quot;MAIL SMTP&amp;quot;, &amp;quot;tnum&amp;quot; : 9, &amp;quot;tname&amp;quot; : &amp;quot;team9&amp;quot;, &amp;quot;status&amp;quot; : &amp;quot;Status: 2&amp;quot; }
{ &amp;quot;group&amp;quot; : &amp;quot;MAIL SMTP&amp;quot;, &amp;quot;tnum&amp;quot; : 10, &amp;quot;tname&amp;quot; : &amp;quot;team10&amp;quot;, &amp;quot;status&amp;quot; : &amp;quot;Status: 2&amp;quot; }
...
&lt;/code&gt;&lt;/pre&gt;

&lt;h5 id=&#34;get-service-list-form-results:d680e8a854a7cbad6d490c445cba2eba&#34;&gt;Get service list form results&lt;/h5&gt;

&lt;p&gt;Query&lt;/p&gt;

&lt;pre&gt;&lt;code&gt;db.results.aggregate(
    {&amp;quot;$match&amp;quot;: {&amp;quot;type&amp;quot;: &amp;quot;Service&amp;quot;}},
    {&amp;quot;$group&amp;quot;: {&amp;quot;_id&amp;quot;: &amp;quot;$group&amp;quot;}},
    {&amp;quot;$project&amp;quot;: {&amp;quot;_id&amp;quot;: 0, &amp;quot;group&amp;quot;: &amp;quot;$_id&amp;quot;}}
)
&lt;/code&gt;&lt;/pre&gt;

&lt;p&gt;Results&lt;/p&gt;

&lt;pre&gt;&lt;code&gt;{ &amp;quot;group&amp;quot; : &amp;quot;WWW SSH&amp;quot; }
{ &amp;quot;group&amp;quot; : &amp;quot;MAIL POP&amp;quot; }
{ &amp;quot;group&amp;quot; : &amp;quot;MAIL SMTP&amp;quot; }
{ &amp;quot;group&amp;quot; : &amp;quot;ROUTER PING&amp;quot; }
{ &amp;quot;group&amp;quot; : &amp;quot;WWW 80&amp;quot; }
&lt;/code&gt;&lt;/pre&gt;

&lt;h5 id=&#34;get-ctf-list-form-results:d680e8a854a7cbad6d490c445cba2eba&#34;&gt;Get CTF list form results&lt;/h5&gt;

&lt;p&gt;Query&lt;/p&gt;

&lt;pre&gt;&lt;code&gt;db.results.aggregate(
    {&amp;quot;$match&amp;quot;: {&amp;quot;type&amp;quot;: &amp;quot;CTF&amp;quot;}},
    {&amp;quot;$group&amp;quot;: {&amp;quot;_id&amp;quot;: &amp;quot;$group&amp;quot;}},
    {&amp;quot;$project&amp;quot;: {&amp;quot;_id&amp;quot;: 0, &amp;quot;group&amp;quot;: &amp;quot;$_id&amp;quot;}}
)
&lt;/code&gt;&lt;/pre&gt;

&lt;p&gt;Results&lt;/p&gt;

&lt;pre&gt;&lt;code&gt;{ &amp;quot;group&amp;quot; : &amp;quot;Misc-Enumeration&amp;quot; }
{ &amp;quot;group&amp;quot; : &amp;quot;Rusted Bunions&amp;quot; }
{ &amp;quot;group&amp;quot; : &amp;quot;SIGNUP&amp;quot; }
{ &amp;quot;group&amp;quot; : &amp;quot;CTF-Web&amp;quot; }
&lt;/code&gt;&lt;/pre&gt;

&lt;h5 id=&#34;group-by-challenge-and-get-the-total-amount-of-challenge-and-the-total-points:d680e8a854a7cbad6d490c445cba2eba&#34;&gt;Group by challenge and get the total amount of challenge and the total points&lt;/h5&gt;

&lt;p&gt;Query&lt;/p&gt;

&lt;pre&gt;&lt;code&gt;db.challenges.aggregate(
    {&amp;quot;$group&amp;quot;: 
        {
            &amp;quot;_id&amp;quot;: &amp;quot;$group&amp;quot;,
            &amp;quot;total challenges&amp;quot;: {&amp;quot;$sum&amp;quot;: 1},
            &amp;quot;total points&amp;quot;: {&amp;quot;$sum&amp;quot;: &amp;quot;$points&amp;quot;}
        }
    },
    {&amp;quot;$sort&amp;quot;: {&amp;quot;_id&amp;quot;: 1}}
)
&lt;/code&gt;&lt;/pre&gt;

&lt;p&gt;Result&lt;/p&gt;

&lt;pre&gt;&lt;code&gt;{ &amp;quot;_id&amp;quot; : &amp;quot;CTF-Web&amp;quot;, &amp;quot;total challenges&amp;quot; : 16, &amp;quot;total points&amp;quot; : 100 }
{ &amp;quot;_id&amp;quot; : &amp;quot;CentOS&amp;quot;, &amp;quot;total challenges&amp;quot; : 3, &amp;quot;total points&amp;quot; : 40 }
{ &amp;quot;_id&amp;quot; : &amp;quot;Misc-Enumeration&amp;quot;, &amp;quot;total challenges&amp;quot; : 100, &amp;quot;total points&amp;quot; : 100 }
{ &amp;quot;_id&amp;quot; : &amp;quot;Rusted Bunions&amp;quot;, &amp;quot;total challenges&amp;quot; : 7, &amp;quot;total points&amp;quot; : 395 }
{ &amp;quot;_id&amp;quot; : &amp;quot;SIGNUP&amp;quot;, &amp;quot;total challenges&amp;quot; : 2, &amp;quot;total points&amp;quot; : 3 }
{ &amp;quot;_id&amp;quot; : &amp;quot;Win-XP&amp;quot;, &amp;quot;total challenges&amp;quot; : 7, &amp;quot;total points&amp;quot; : 65 }
&lt;/code&gt;&lt;/pre&gt;

&lt;h5 id=&#34;get-the-amount-of-challenges-a-certain-team-obtained:d680e8a854a7cbad6d490c445cba2eba&#34;&gt;Get the amount of challenges a certain team obtained&lt;/h5&gt;

&lt;p&gt;Query&lt;/p&gt;

&lt;pre&gt;&lt;code&gt;db.results.aggregate(
    {&amp;quot;$match&amp;quot;: {&amp;quot;teamname&amp;quot;: &amp;quot;team1&amp;quot;, &amp;quot;type&amp;quot;: &amp;quot;CTF&amp;quot;}},
    {&amp;quot;$group&amp;quot;: {&amp;quot;_id&amp;quot;: &amp;quot;$group&amp;quot;, &amp;quot;acquired&amp;quot;: {&amp;quot;$sum&amp;quot;: 1}}},
    {&amp;quot;$sort&amp;quot;: {&amp;quot;_id&amp;quot;: 1}}
)
&lt;/code&gt;&lt;/pre&gt;

&lt;p&gt;Result&lt;/p&gt;

&lt;pre&gt;&lt;code&gt;{ &amp;quot;_id&amp;quot; : &amp;quot;Rusted Bunions&amp;quot;, &amp;quot;acquired&amp;quot; : 2 }
{ &amp;quot;_id&amp;quot; : &amp;quot;SIGNUP&amp;quot;, &amp;quot;acquired&amp;quot; : 1 }
&lt;/code&gt;&lt;/pre&gt;

&lt;h5 id=&#34;same-as-above-except-with-the-total-points:d680e8a854a7cbad6d490c445cba2eba&#34;&gt;Same as above except with the total points&lt;/h5&gt;

&lt;p&gt;Query&lt;/p&gt;

&lt;pre&gt;&lt;code&gt;db.results.aggregate(
    {&amp;quot;$match&amp;quot;: {&amp;quot;teamname&amp;quot;: &amp;quot;team10&amp;quot;, &amp;quot;type&amp;quot;: &amp;quot;CTF&amp;quot;}},
    {&amp;quot;$group&amp;quot;: {&amp;quot;_id&amp;quot;: &amp;quot;$group&amp;quot;, &amp;quot;acquired&amp;quot;: {&amp;quot;$sum&amp;quot;: 1}}},
    {&amp;quot;$sort&amp;quot;: {&amp;quot;_id&amp;quot;: 1}}
)
&lt;/code&gt;&lt;/pre&gt;

&lt;p&gt;Result&lt;/p&gt;

&lt;pre&gt;&lt;code&gt;{ &amp;quot;_id&amp;quot; : &amp;quot;Misc-Enumeration&amp;quot;, &amp;quot;acquired&amp;quot; : 8, &amp;quot;points&amp;quot; : 8 }
{ &amp;quot;_id&amp;quot; : &amp;quot;Rusted Bunions&amp;quot;, &amp;quot;acquired&amp;quot; : 4, &amp;quot;points&amp;quot; : 125 }
{ &amp;quot;_id&amp;quot; : &amp;quot;SIGNUP&amp;quot;, &amp;quot;acquired&amp;quot; : 2, &amp;quot;points&amp;quot; : 3 }
&lt;/code&gt;&lt;/pre&gt;

&lt;h5 id=&#34;get-a-team-score-and-only-output-the-points:d680e8a854a7cbad6d490c445cba2eba&#34;&gt;Get a team score and only output the points&lt;/h5&gt;

&lt;p&gt;Query&lt;/p&gt;

&lt;pre&gt;&lt;code&gt;db.results.aggregate(
    {&amp;quot;$match&amp;quot;: {&amp;quot;teamname&amp;quot;: &amp;quot;team3&amp;quot;}},
    {&amp;quot;$group&amp;quot;: 
        {
            &amp;quot;_id&amp;quot;: null,
            &amp;quot;points&amp;quot;: {&amp;quot;$sum&amp;quot;: &amp;quot;$points&amp;quot;}
        }
    },
    {&amp;quot;$project&amp;quot;: {&amp;quot;_id&amp;quot;: 0, &amp;quot;points&amp;quot;: 1}}
)
&lt;/code&gt;&lt;/pre&gt;

&lt;p&gt;Result&lt;/p&gt;

&lt;pre&gt;&lt;code&gt;{ &amp;quot;points&amp;quot; : 758 }
&lt;/code&gt;&lt;/pre&gt;

&lt;h5 id=&#34;get-all-team-scores:d680e8a854a7cbad6d490c445cba2eba&#34;&gt;Get all team scores&lt;/h5&gt;

&lt;p&gt;Query&lt;/p&gt;

&lt;pre&gt;&lt;code&gt;db.results.aggregate(
    {&amp;quot;$group&amp;quot;: 
        {
            &amp;quot;_id&amp;quot;: {&amp;quot;tname&amp;quot;: &amp;quot;$teamname&amp;quot;, &amp;quot;tnum&amp;quot;: &amp;quot;$teamnumber&amp;quot;},
            &amp;quot;points&amp;quot;: {&amp;quot;$sum&amp;quot;: &amp;quot;$points&amp;quot;}
        }
    },
    {&amp;quot;$project&amp;quot;: 
        {
            &amp;quot;_id&amp;quot;: 0,
            &amp;quot;points&amp;quot;: 1,
            &amp;quot;teamnumber&amp;quot;: &amp;quot;$_id.tnum&amp;quot;, 
            &amp;quot;teamname&amp;quot;: &amp;quot;$_id.tname&amp;quot;
        }
    },
    {&amp;quot;$sort&amp;quot;: {&amp;quot;teamnumber&amp;quot;: 1}} 
)
&lt;/code&gt;&lt;/pre&gt;

&lt;p&gt;Result&lt;/p&gt;

&lt;pre&gt;&lt;code&gt;{ &amp;quot;points&amp;quot; : 485, &amp;quot;teamnumber&amp;quot; : 1, &amp;quot;teamname&amp;quot; : &amp;quot;team1&amp;quot; }
{ &amp;quot;points&amp;quot; : 558, &amp;quot;teamnumber&amp;quot; : 2, &amp;quot;teamname&amp;quot; : &amp;quot;team2&amp;quot; }
{ &amp;quot;points&amp;quot; : 758, &amp;quot;teamnumber&amp;quot; : 3, &amp;quot;teamname&amp;quot; : &amp;quot;team3&amp;quot; }
{ &amp;quot;points&amp;quot; : 691, &amp;quot;teamnumber&amp;quot; : 4, &amp;quot;teamname&amp;quot; : &amp;quot;team4&amp;quot; }
{ &amp;quot;points&amp;quot; : 512, &amp;quot;teamnumber&amp;quot; : 5, &amp;quot;teamname&amp;quot; : &amp;quot;team5&amp;quot; }
{ &amp;quot;points&amp;quot; : 649, &amp;quot;teamnumber&amp;quot; : 6, &amp;quot;teamname&amp;quot; : &amp;quot;team6&amp;quot; }
{ &amp;quot;points&amp;quot; : 497, &amp;quot;teamnumber&amp;quot; : 7, &amp;quot;teamname&amp;quot; : &amp;quot;team7&amp;quot; }
{ &amp;quot;points&amp;quot; : 502, &amp;quot;teamnumber&amp;quot; : 8, &amp;quot;teamname&amp;quot; : &amp;quot;team8&amp;quot; }
{ &amp;quot;points&amp;quot; : 379, &amp;quot;teamnumber&amp;quot; : 9, &amp;quot;teamname&amp;quot; : &amp;quot;team9&amp;quot; }
{ &amp;quot;points&amp;quot; : 459, &amp;quot;teamnumber&amp;quot; : 10, &amp;quot;teamname&amp;quot; : &amp;quot;team10&amp;quot; }
&lt;/code&gt;&lt;/pre&gt;

&lt;h5 id=&#34;get-last-status-of-each-team-by-service:d680e8a854a7cbad6d490c445cba2eba&#34;&gt;Get last status of each team by service&lt;/h5&gt;

&lt;p&gt;Query&lt;/p&gt;

&lt;pre&gt;&lt;code&gt;db.results.aggregate(
    {&amp;quot;$match&amp;quot;: {&amp;quot;type&amp;quot;: &amp;quot;Service&amp;quot;, &amp;quot;group&amp;quot;: &amp;quot;ROUTER PING&amp;quot;}},
    {&amp;quot;$group&amp;quot;: 
        {
            &amp;quot;_id&amp;quot;: {&amp;quot;service&amp;quot;: &amp;quot;$group&amp;quot;, &amp;quot;tnum&amp;quot;: &amp;quot;$teamnumber&amp;quot;, &amp;quot;tname&amp;quot;: &amp;quot;$teamname&amp;quot;}, 
            &amp;quot;status&amp;quot;: {&amp;quot;$last&amp;quot;: &amp;quot;$details&amp;quot;}
        }
    },
    {&amp;quot;$project&amp;quot;: 
        {
            &amp;quot;_id&amp;quot;: 0,
            &amp;quot;group&amp;quot;: &amp;quot;$_id.service&amp;quot;,
            &amp;quot;teamnumber&amp;quot;: &amp;quot;$_id.tnum&amp;quot;,
            &amp;quot;teamname&amp;quot;: &amp;quot;$_id.tname&amp;quot;,
            &amp;quot;details&amp;quot;: &amp;quot;$status&amp;quot;
        }
    },
    {&amp;quot;$sort&amp;quot;: {&amp;quot;teamnumber&amp;quot;: 1}}
)
&lt;/code&gt;&lt;/pre&gt;

&lt;p&gt;Result&lt;/p&gt;

&lt;pre&gt;&lt;code&gt;{ &amp;quot;group&amp;quot; : &amp;quot;ROUTER PING&amp;quot;, &amp;quot;teamnumber&amp;quot; : 1, &amp;quot;teamname&amp;quot; : &amp;quot;team1&amp;quot;, &amp;quot;details&amp;quot; : &amp;quot;Status: 0&amp;quot; }
{ &amp;quot;group&amp;quot; : &amp;quot;ROUTER PING&amp;quot;, &amp;quot;teamnumber&amp;quot; : 2, &amp;quot;teamname&amp;quot; : &amp;quot;team2&amp;quot;, &amp;quot;details&amp;quot; : &amp;quot;Status: 0&amp;quot; }
{ &amp;quot;group&amp;quot; : &amp;quot;ROUTER PING&amp;quot;, &amp;quot;teamnumber&amp;quot; : 3, &amp;quot;teamname&amp;quot; : &amp;quot;team3&amp;quot;, &amp;quot;details&amp;quot; : &amp;quot;Status: 0&amp;quot; }
{ &amp;quot;group&amp;quot; : &amp;quot;ROUTER PING&amp;quot;, &amp;quot;teamnumber&amp;quot; : 4, &amp;quot;teamname&amp;quot; : &amp;quot;team4&amp;quot;, &amp;quot;details&amp;quot; : &amp;quot;Status: 0&amp;quot; }
{ &amp;quot;group&amp;quot; : &amp;quot;ROUTER PING&amp;quot;, &amp;quot;teamnumber&amp;quot; : 5, &amp;quot;teamname&amp;quot; : &amp;quot;team5&amp;quot;, &amp;quot;details&amp;quot; : &amp;quot;Status: 0&amp;quot; }
{ &amp;quot;group&amp;quot; : &amp;quot;ROUTER PING&amp;quot;, &amp;quot;teamnumber&amp;quot; : 6, &amp;quot;teamname&amp;quot; : &amp;quot;team6&amp;quot;, &amp;quot;details&amp;quot; : &amp;quot;Status: 0&amp;quot; }
{ &amp;quot;group&amp;quot; : &amp;quot;ROUTER PING&amp;quot;, &amp;quot;teamnumber&amp;quot; : 7, &amp;quot;teamname&amp;quot; : &amp;quot;team7&amp;quot;, &amp;quot;details&amp;quot; : &amp;quot;Status: 0&amp;quot; }
{ &amp;quot;group&amp;quot; : &amp;quot;ROUTER PING&amp;quot;, &amp;quot;teamnumber&amp;quot; : 8, &amp;quot;teamname&amp;quot; : &amp;quot;team8&amp;quot;, &amp;quot;details&amp;quot; : &amp;quot;Status: 0&amp;quot; }
{ &amp;quot;group&amp;quot; : &amp;quot;ROUTER PING&amp;quot;, &amp;quot;teamnumber&amp;quot; : 9, &amp;quot;teamname&amp;quot; : &amp;quot;team9&amp;quot;, &amp;quot;details&amp;quot; : &amp;quot;Status: 0&amp;quot; }
{ &amp;quot;group&amp;quot; : &amp;quot;ROUTER PING&amp;quot;, &amp;quot;teamnumber&amp;quot; : 10, &amp;quot;teamname&amp;quot; : &amp;quot;team10&amp;quot;, &amp;quot;details&amp;quot; : &amp;quot;Status: 0&amp;quot; }
&lt;/code&gt;&lt;/pre&gt;

&lt;h5 id=&#34;get-the-objectid-of-the-last-document-in-results:d680e8a854a7cbad6d490c445cba2eba&#34;&gt;Get the ObjectID of the last document in results&lt;/h5&gt;

&lt;p&gt;Query&lt;/p&gt;

&lt;pre&gt;&lt;code&gt;db.results.aggregate(
    {&amp;quot;$sort&amp;quot;: {&amp;quot;_id&amp;quot;: 1}},
    {&amp;quot;$group&amp;quot;: {&amp;quot;_id&amp;quot;: null, &amp;quot;last&amp;quot;: {&amp;quot;$last&amp;quot;: &amp;quot;$_id&amp;quot;}}},
    {&amp;quot;$project&amp;quot;: {&amp;quot;_id&amp;quot;: 0, &amp;quot;last&amp;quot;: 1}}
)
&lt;/code&gt;&lt;/pre&gt;

&lt;p&gt;Result&lt;/p&gt;

&lt;pre&gt;&lt;code&gt;{ &amp;quot;last&amp;quot; : ObjectId(&amp;quot;571be338afbeb9566a40683d&amp;quot;) }
&lt;/code&gt;&lt;/pre&gt;

&lt;h5 id=&#34;get-the-objectid-of-the-last-document-that-is-type-service-in-results:d680e8a854a7cbad6d490c445cba2eba&#34;&gt;Get the ObjectID of the last document that is type &amp;ldquo;Service&amp;rdquo; in results&lt;/h5&gt;

&lt;p&gt;Query&lt;/p&gt;

&lt;pre&gt;&lt;code&gt;db.results.aggregate(
    {&amp;quot;$match&amp;quot;: {&amp;quot;type&amp;quot;: &amp;quot;Service&amp;quot;}},
    {&amp;quot;$sort&amp;quot;: {&amp;quot;_id&amp;quot;: 1}},
    {&amp;quot;$group&amp;quot;: {&amp;quot;_id&amp;quot;: null, &amp;quot;last&amp;quot;: {&amp;quot;$last&amp;quot;: &amp;quot;$_id&amp;quot;}}},
    {&amp;quot;$project&amp;quot;: {&amp;quot;_id&amp;quot;: 0, &amp;quot;last&amp;quot;: 1}}
)
&lt;/code&gt;&lt;/pre&gt;

&lt;p&gt;Result&lt;/p&gt;

&lt;pre&gt;&lt;code&gt;{ &amp;quot;last&amp;quot; : ObjectId(&amp;quot;571be265afbeb9566a406839&amp;quot;) }
&lt;/code&gt;&lt;/pre&gt;

&lt;h5 id=&#34;get-the-amount-of-documents-grouped-by-group:d680e8a854a7cbad6d490c445cba2eba&#34;&gt;Get the amount of documents grouped by group&lt;/h5&gt;

&lt;p&gt;Query&lt;/p&gt;

&lt;pre&gt;&lt;code&gt;db.results.aggregate(
    {&amp;quot;$group&amp;quot;:
        {
            &amp;quot;_id&amp;quot;: &amp;quot;$group&amp;quot;,
            &amp;quot;total&amp;quot;: {&amp;quot;$sum&amp;quot;: 1}
        }
    },
    {&amp;quot;$sort&amp;quot;: {&amp;quot;_id&amp;quot;: 1}}
)
&lt;/code&gt;&lt;/pre&gt;

&lt;p&gt;Result&lt;/p&gt;

&lt;pre&gt;&lt;code&gt;{ &amp;quot;_id&amp;quot; : &amp;quot;CTF-Web&amp;quot;, &amp;quot;total&amp;quot; : 13 }
{ &amp;quot;_id&amp;quot; : &amp;quot;Extra&amp;quot;, &amp;quot;total&amp;quot; : 1 }
{ &amp;quot;_id&amp;quot; : &amp;quot;MAIL POP&amp;quot;, &amp;quot;total&amp;quot; : 1173 }
{ &amp;quot;_id&amp;quot; : &amp;quot;MAIL SMTP&amp;quot;, &amp;quot;total&amp;quot; : 1171 }
{ &amp;quot;_id&amp;quot; : &amp;quot;Misc-Enumeration&amp;quot;, &amp;quot;total&amp;quot; : 28 }
{ &amp;quot;_id&amp;quot; : &amp;quot;ROUTER PING&amp;quot;, &amp;quot;total&amp;quot; : 1279 }
{ &amp;quot;_id&amp;quot; : &amp;quot;Rusted Bunions&amp;quot;, &amp;quot;total&amp;quot; : 31 }
{ &amp;quot;_id&amp;quot; : &amp;quot;SIGNUP&amp;quot;, &amp;quot;total&amp;quot; : 17 }
{ &amp;quot;_id&amp;quot; : &amp;quot;WWW 80&amp;quot;, &amp;quot;total&amp;quot; : 1271 }
{ &amp;quot;_id&amp;quot; : &amp;quot;WWW SSH&amp;quot;, &amp;quot;total&amp;quot; : 1174 }
&lt;/code&gt;&lt;/pre&gt;

&lt;h5 id=&#34;same-as-above-except-with-total-points:d680e8a854a7cbad6d490c445cba2eba&#34;&gt;Same as above except with total points&lt;/h5&gt;

&lt;p&gt;Query&lt;/p&gt;

&lt;pre&gt;&lt;code&gt;db.results.aggregate(
    {&amp;quot;$group&amp;quot;:
        {
            &amp;quot;_id&amp;quot;: &amp;quot;$group&amp;quot;,
            &amp;quot;total&amp;quot;: {&amp;quot;$sum&amp;quot;: 1},
            &amp;quot;points&amp;quot;: {&amp;quot;$sum&amp;quot;: &amp;quot;$points&amp;quot;}
        }
    },
    {&amp;quot;$sort&amp;quot;: {&amp;quot;_id&amp;quot;: 1}}
)
&lt;/code&gt;&lt;/pre&gt;

&lt;p&gt;Result&lt;/p&gt;

&lt;pre&gt;&lt;code&gt;{ &amp;quot;_id&amp;quot; : &amp;quot;CTF-Web&amp;quot;, &amp;quot;amt&amp;quot; : 13, &amp;quot;points&amp;quot; : 80 }
{ &amp;quot;_id&amp;quot; : &amp;quot;Extra&amp;quot;, &amp;quot;amt&amp;quot; : 1, &amp;quot;points&amp;quot; : 250 }
{ &amp;quot;_id&amp;quot; : &amp;quot;MAIL POP&amp;quot;, &amp;quot;amt&amp;quot; : 1173, &amp;quot;points&amp;quot; : 104 }
{ &amp;quot;_id&amp;quot; : &amp;quot;MAIL SMTP&amp;quot;, &amp;quot;amt&amp;quot; : 1171, &amp;quot;points&amp;quot; : 15 }
{ &amp;quot;_id&amp;quot; : &amp;quot;Misc-Enumeration&amp;quot;, &amp;quot;amt&amp;quot; : 28, &amp;quot;points&amp;quot; : 28 }
{ &amp;quot;_id&amp;quot; : &amp;quot;ROUTER PING&amp;quot;, &amp;quot;amt&amp;quot; : 1279, &amp;quot;points&amp;quot; : 2561 }
{ &amp;quot;_id&amp;quot; : &amp;quot;Rusted Bunions&amp;quot;, &amp;quot;amt&amp;quot; : 31, &amp;quot;points&amp;quot; : 1055 }
{ &amp;quot;_id&amp;quot; : &amp;quot;SIGNUP&amp;quot;, &amp;quot;amt&amp;quot; : 17, &amp;quot;points&amp;quot; : 22 }
{ &amp;quot;_id&amp;quot; : &amp;quot;WWW 80&amp;quot;, &amp;quot;amt&amp;quot; : 1271, &amp;quot;points&amp;quot; : 1057 }
{ &amp;quot;_id&amp;quot; : &amp;quot;WWW SSH&amp;quot;, &amp;quot;amt&amp;quot; : 1174, &amp;quot;points&amp;quot; : 318 }
&lt;/code&gt;&lt;/pre&gt;
</description>
    </item>
    
  </channel>
</rss>