Class ExpressionWrapper<DB, TB, T>

Change the output type of the expression.

This method call doesn't change the SQL in any way. This methods simply returns a copy of this ExpressionWrapper with a new output type.

Combines this and another expression using AND.

Also see and

Examples

db.selectFrom('person')
  .selectAll()
  .where(eb => eb('first_name', '=', 'Jennifer')
    .and('last_name', '=', 'Aniston')
    .and('age', '>', 40)
  )
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The generated SQL (PostgreSQL):

select *
from "person"
where (
  "first_name" = $1
  and "last_name" = $2
  and "age" > $3
)
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You can also pass any expression as the only argument to this method:

db.selectFrom('person')
  .selectAll()
  .where(eb => eb('first_name', '=', 'Jennifer')
    .and(eb('first_name', '=', 'Sylvester').or('last_name', '=', 'Stallone'))
    .and(eb.exists(
      eb.selectFrom('pet')
        .select('id')
        .whereRef('pet.owner_id', '=', 'person.id')
    )
  )
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The generated SQL (PostgreSQL):

select *
from "person"
where (
  "first_name" = $1
  and ("first_name" = $2 or "last_name" = $3)
  and exists (
    select "id"
    from "pet"
    where "pet"."owner_id" = "person"."id"
  )
)
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Returns an aliased version of the expression.

In addition to slapping as "the_alias" to the end of the SQL, this method also provides strict typing:

const result = await db
  .selectFrom('person')
  .select((eb) =>
    eb('first_name', '=', 'Jennifer').as('is_jennifer')
  )
  .executeTakeFirstOrThrow()

// `is_jennifer: SqlBool` field exists in the result type.
console.log(result.is_jennifer)
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The generated SQL (PostgreSQL):

select "first_name" = $1 as "is_jennifer"
from "person"
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Combines this and another expression using OR.

Also see or

Examples

db.selectFrom('person')
  .selectAll()
  .where(eb => eb('first_name', '=', 'Jennifer')
    .or('first_name', '=', 'Arnold')
    .or('first_name', '=', 'Sylvester')
  )
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The generated SQL (PostgreSQL):

select *
from "person"
where (
  "first_name" = $1
  or "first_name" = $2
  or "first_name" = $3
)
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You can also pass any expression as the only argument to this method:

db.selectFrom('person')
  .selectAll()
  .where(eb => eb('first_name', '=', 'Jennifer')
    .or(eb('first_name', '=', 'Sylvester').and('last_name', '=', 'Stallone'))
    .or(eb.exists(
      eb.selectFrom('pet')
        .select('id')
        .whereRef('pet.owner_id', '=', 'person.id')
    )
  )
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The generated SQL (PostgreSQL):

select *
from "person"
where (
  "first_name" = $1
  or ("first_name" = $2 and "last_name" = $3)
  or exists (
    select "id"
    from "pet"
    where "pet"."owner_id" = "person"."id"
  )
)
Copy

Creates the OperationNode that describes how to compile this expression into SQL.

If you are creating a custom expression, it's often easiest to use the sql template tag to build the node:

class SomeExpression<T> implements Expression<T> {
  toOperationNode(): OperationNode {
    return sql`some sql here`.toOperationNode()
  }
}
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