Feat: Set operations (union / intersect / except) support

[Angelelz]

This PR will close #207

[Angelelz]

In its most basic form, upon merging this PR, a drizzle user will be able to create queries with union / intersect / except {all} statements with the following syntax:

await db.select().from(table)
  .union(
    db.select().from(table)
  );

Beyond that, given the following queries:

const query1 = db
  .select({ id: users.id, name: users.name })
  .from(users)
  .where(eq(users.id, 1))
  .leftJoin(posts, eq(users.id, posts.authorId));

const query2 = db
  .select({ id: users.id, name: sql<string>`users.name` })
  .from(users)
  .where(eq(users.id, 2));

const query3 = db
  .select({ id: users.id, name: users.name })
  .from(users)
  .where(eq(users.id, 3));

const query4 = db
  .select({ id: users.id, name: sql<string>`users.name` })
  .from(users)
  .where(eq(users.id, 4))
  .leftJoin(posts, eq(users.id, posts.authorId));

const query5 = db
  .select({ id: users.id, name: users.name })
  .from(users)
  .where(eq(users.id, 5));

const query6 = db
  .select({ id: users.id, name: users.name })
  .from(users)
  .where(eq(users.id, 2));

All of the following are valid drizzle syntax:

const result1 = await union(
  query1,
  query2,
  intersect(query3, query4, query5),
  query6,
).orderBy(desc(users.id))

const result2 = await union(
  union(
    union(query1, query2),
    intersect(intersect(query3, query4), query5),
  ),
  query6,
)

const result3 = await query1
  .union(query2)
  .union(query3.intersect(query4).intersect(query5))
  .union(query6)

const result4 = await query1
  .union(query2)
  .union(({ intersect }) => intersect(query3, query4, query5))
  .union(query6)

And will all result in the same query (MySql and Postgres):
Keep in mind that the queries are mutable, so if those 4 queries are run one after the other, the results would be unexpected.

"(((select \"users\".\"id\", \"users\".\"name\" from \"users\" left join \"posts\" on \"users\".\"id\" = \"posts\".\"author_id\"
where \"users\".\"id\" = $1) union (select \"id\", users.name from \"users\" where \"users\".\"id\" = $2))
union (((select \"id\", \"name\" from \"users\" where \"users\".\"id\" = $3) intersect (select \"users\".\"id\", users.name
from \"users\" left join \"posts\" on \"users\".\"id\" = \"posts\".\"author_id\" where \"users\".\"id\" = $4))
intersect (select \"id\", \"name\" from \"users\" where \"users\".\"id\" = $5)))
union (select \"id\", \"name\" from \"users\" where \"users\".\"id\" = $6)",
params: [ 1, 2, 3, 4, 5, 2 ]

But in SQLite, parenthesis are not allowed, or order by / limit on the left of the set operator clause, so the resulting query will be:

"select \"users\".\"id\", \"users\".\"name\" from \"users\" left join \"posts\" on \"users\".\"id\" = \"posts\".\"author_id\"
where \"users\".\"id\" = ? union select \"id\", users.name from \"users\" where \"users\".\"id\" = ?
union select \"id\", \"name\" from \"users\" where \"users\".\"id\" = ? intersect select \"users\".\"id\", users.name
from \"users\" left join \"posts\" on \"users\".\"id\" = \"posts\".\" author_id\" where \"users\".\"id\" = ?
intersect select \"id\", \"name\" from \"users\" where \"users\".\"id\" = ? union select \"id\", \"name\"
from \"users\" where \"users\".\"id\" = ?",
params: [ 1, 2, 3, 4, 5, 2 ]

Selecting different columns names, with different types or different number of them will result in a type error that if ignored, will result in a runtime error as it will be invalid SQL syntax.

[dankochetov]

Please change the PR's destination to beta instead of main. There were some query builder type changes, so you will probably have some merge conflicts.

Also, you'd need to update the SetOperator classes according to the changes in other query builders.

[enfipy]

Just want to say that I absolutely love this feature and can't wait to see it released! 🔥

[Angelelz]

The implementation is complete.
I included similar types as the rest of the query builders to avoid calling the same method twice.

[datner]

the hype is real, lets gooooooo

[dankochetov]

LET'S GO THE HYPE IS REAL