Update sql-models.md (SQL queries)

[KrishBende]

Column names updated. Slight updates made in query. The SQL code was wrong. Column names were mislabelled and slight changes in query were required.

What are you changing in this pull request and why?

I am changing the column names in the SQL query, since the Orders and Customers tables have different column names.

Checklist

• The changes in this PR meet the docs style guide/fundamentals required for all content.
• Applied the proper versioning rules if the content is for specific dbt version(s): (version a whole page or version a block of content
• The content in this PR requires a dbt release note, so I added one to the release notes page.).

[vercel]

@KrishBende is attempting to deploy a commit to the dbt-labs Team on Vercel.

A member of the Team first needs to authorize it.

[mirnawong1]

hey @KrishBende thnks so much for opening this up! we'll get this reviewed and ensure it aligns with our sql style guide!