Class DeleteQueryBuilder<DB, TB, O>

Asserts that query's output row type equals the given type T.

This method can be used to simplify excessively complex types to make TypeScript happy and much faster.

Kysely uses complex type magic to achieve its type safety. This complexity is sometimes too much for TypeScript and you get errors like this:

error TS2589: Type instantiation is excessively deep and possibly infinite.
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In these case you can often use this method to help TypeScript a little bit. When you use this method to assert the output type of a query, Kysely can drop the complex output type that consists of multiple nested helper types and replace it with the simple asserted type.

Using this method doesn't reduce type safety at all. You have to pass in a type that is structurally equal to the current type.

Examples

import type { Species } from 'type-editor' // imaginary module

async function deletePersonAndPets(personId: number) {
  return await db
    .with('deleted_person', (qb) => qb
       .deleteFrom('person')
       .where('id', '=', personId)
       .returning('first_name')
       .$assertType<{ first_name: string }>()
    )
    .with('deleted_pets', (qb) => qb
      .deleteFrom('pet')
      .where('owner_id', '=', personId)
      .returning(['name as pet_name', 'species'])
      .$assertType<{ pet_name: string, species: Species }>()
    )
    .selectFrom(['deleted_person', 'deleted_pets'])
    .selectAll()
    .execute()
}
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Simply calls the provided function passing this as the only argument. $call returns what the provided function returns.

If you want to conditionally call a method on this, see the $if method.

Examples

The next example uses a helper function log to log a query:

import type { Compilable } from 'kysely'

function log<T extends Compilable>(qb: T): T {
  console.log(qb.compile())
  return qb
}

await db.deleteFrom('person')
  .$call(log)
  .execute()
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Change the output type of the query.

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

Call func(this) if condition is true.

This method is especially handy with optional selects. Any returning or returningAll method calls add columns as optional fields to the output type when called inside the func callback. This is because we can't know if those selections were actually made before running the code.

You can also call any other methods inside the callback.

Examples

async function deletePerson(id: number, returnLastName: boolean) {
  return await db
    .deleteFrom('person')
    .where('id', '=', id)
    .returning(['id', 'first_name'])
    .$if(returnLastName, (qb) => qb.returning('last_name'))
    .executeTakeFirstOrThrow()
}
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Any selections added inside the if callback will be added as optional fields to the output type since we can't know if the selections were actually made before running the code. In the example above the return type of the deletePerson function is:

Promise<{
  id: number
  first_name: string
  last_name?: string
}>
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Narrows (parts of) the output type of the query.

Kysely tries to be as type-safe as possible, but in some cases we have to make compromises for better maintainability and compilation performance. At present, Kysely doesn't narrow the output type of the query when using where and returning or returningAll.

This utility method is very useful for these situations, as it removes unncessary runtime assertion/guard code. Its input type is limited to the output type of the query, so you can't add a column that doesn't exist, or change a column's type to something that doesn't exist in its union type.

Examples

Turn this code:

import type { Person } from 'type-editor' // imaginary module

const person = await db.deleteFrom('person')
  .where('id', '=', 3)
  .where('nullable_column', 'is not', null)
  .returningAll()
  .executeTakeFirstOrThrow()

if (isWithNoNullValue(person)) {
  functionThatExpectsPersonWithNonNullValue(person)
}

function isWithNoNullValue(person: Person): person is Person & { nullable_column: string } {
  return person.nullable_column != null
}
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Into this:

import type { NotNull } from 'kysely'

const person = await db.deleteFrom('person')
  .where('id', '=', 3)
  .where('nullable_column', 'is not', null)
  .returningAll()
  .$narrowType<{ nullable_column: NotNull }>()
  .executeTakeFirstOrThrow()

functionThatExpectsPersonWithNonNullValue(person)
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Clears the limit clause from the query.

Examples

await db.deleteFrom('pet')
  .returningAll()
  .where('name', '=', 'Max')
  .limit(5)
  .clearLimit()
  .execute()
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The generated SQL(PostgreSQL):

delete from "pet" where "name" = "Max" returning *
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Clears the order by clause from the query.

See orderBy for adding an order by clause or item to a query.

Examples

const query = db
  .selectFrom('person')
  .selectAll()
  .orderBy('id', 'desc')

const results = await query
  .clearOrderBy()
  .execute()
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The generated SQL (PostgreSQL):

select * from "person"
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Clears all returning clauses from the query.

Examples

await db.deleteFrom('pet')
  .returningAll()
  .where('name', '=', 'Max')
  .clearReturning()
  .execute()
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The generated SQL(PostgreSQL):

delete from "pet" where "name" = "Max"
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Clears all where expressions from the query.

Examples

db.selectFrom('person')
  .selectAll()
  .where('id','=',42)
  .clearWhere()
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The generated SQL(PostgreSQL):

select * from "person"
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Executes the query and returns an array of rows.

Also see the executeTakeFirst and executeTakeFirstOrThrow methods.

Executes the query and returns the first result or undefined if the query returned no result.

Executes the query and returns the first result or throws if the query returned no result.

By default an instance of NoResultError is thrown, but you can provide a custom error class, or callback as the only argument to throw a different error.

Executes query with explain statement before the main query.

const explained = await db
 .selectFrom('person')
 .where('gender', '=', 'female')
 .selectAll()
 .explain('json')
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The generated SQL (MySQL):

explain format=json select * from `person` where `gender` = ?
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You can also execute explain analyze statements.

import { sql } from 'kysely'

const explained = await db
 .selectFrom('person')
 .where('gender', '=', 'female')
 .selectAll()
 .explain('json', sql`analyze`)
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The generated SQL (PostgreSQL):

explain (analyze, format json) select * from "person" where "gender" = $1
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Just like innerJoin but adds a full join instead of an inner join.

Just like innerJoin but adds a full join instead of an inner join.

Joins another table to the query using an inner join.

Examples

Simple usage by providing a table name and two columns to join:

const result = await db
  .selectFrom('person')
  .innerJoin('pet', 'pet.owner_id', 'person.id')
  // `select` needs to come after the call to `innerJoin` so
  // that you can select from the joined table.
  .select(['person.id', 'pet.name'])
  .execute()

result[0].id
result[0].name
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The generated SQL (PostgreSQL):

select "person"."id", "pet"."name"
from "person"
inner join "pet"
on "pet"."owner_id" = "person"."id"
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You can give an alias for the joined table like this:

await db.selectFrom('person')
  .innerJoin('pet as p', 'p.owner_id', 'person.id')
  .where('p.name', '=', 'Doggo')
  .selectAll()
  .execute()
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The generated SQL (PostgreSQL):

select *
from "person"
inner join "pet" as "p"
on "p"."owner_id" = "person"."id"
where "p".name" = $1
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You can provide a function as the second argument to get a join builder for creating more complex joins. The join builder has a bunch of on* methods for building the on clause of the join. There's basically an equivalent for every where method (on, onRef, onExists etc.). You can do all the same things with the on method that you can with the corresponding where method. See the where method documentation for more examples.

await db.selectFrom('person')
  .innerJoin(
    'pet',
    (join) => join
      .onRef('pet.owner_id', '=', 'person.id')
      .on('pet.name', '=', 'Doggo')
  )
  .selectAll()
  .execute()
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The generated SQL (PostgreSQL):

select *
from "person"
inner join "pet"
on "pet"."owner_id" = "person"."id"
and "pet"."name" = $1
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You can join a subquery by providing a select query (or a callback) as the first argument:

await db.selectFrom('person')
  .innerJoin(
    db.selectFrom('pet')
      .select(['owner_id', 'name'])
      .where('name', '=', 'Doggo')
      .as('doggos'),
    'doggos.owner_id',
    'person.id',
  )
  .selectAll()
  .execute()
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The generated SQL (PostgreSQL):

select *
from "person"
inner join (
  select "owner_id", "name"
  from "pet"
  where "name" = $1
) as "doggos"
on "doggos"."owner_id" = "person"."id"
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Joins another table to the query using an inner join.

Examples

Simple usage by providing a table name and two columns to join:

const result = await db
  .selectFrom('person')
  .innerJoin('pet', 'pet.owner_id', 'person.id')
  // `select` needs to come after the call to `innerJoin` so
  // that you can select from the joined table.
  .select(['person.id', 'pet.name'])
  .execute()

result[0].id
result[0].name
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The generated SQL (PostgreSQL):

select "person"."id", "pet"."name"
from "person"
inner join "pet"
on "pet"."owner_id" = "person"."id"
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You can give an alias for the joined table like this:

await db.selectFrom('person')
  .innerJoin('pet as p', 'p.owner_id', 'person.id')
  .where('p.name', '=', 'Doggo')
  .selectAll()
  .execute()
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The generated SQL (PostgreSQL):

select *
from "person"
inner join "pet" as "p"
on "p"."owner_id" = "person"."id"
where "p".name" = $1
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You can provide a function as the second argument to get a join builder for creating more complex joins. The join builder has a bunch of on* methods for building the on clause of the join. There's basically an equivalent for every where method (on, onRef, onExists etc.). You can do all the same things with the on method that you can with the corresponding where method. See the where method documentation for more examples.

await db.selectFrom('person')
  .innerJoin(
    'pet',
    (join) => join
      .onRef('pet.owner_id', '=', 'person.id')
      .on('pet.name', '=', 'Doggo')
  )
  .selectAll()
  .execute()
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The generated SQL (PostgreSQL):

select *
from "person"
inner join "pet"
on "pet"."owner_id" = "person"."id"
and "pet"."name" = $1
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You can join a subquery by providing a select query (or a callback) as the first argument:

await db.selectFrom('person')
  .innerJoin(
    db.selectFrom('pet')
      .select(['owner_id', 'name'])
      .where('name', '=', 'Doggo')
      .as('doggos'),
    'doggos.owner_id',
    'person.id',
  )
  .selectAll()
  .execute()
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The generated SQL (PostgreSQL):

select *
from "person"
inner join (
  select "owner_id", "name"
  from "pet"
  where "name" = $1
) as "doggos"
on "doggos"."owner_id" = "person"."id"
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Just like innerJoin but adds a left join instead of an inner join.

Just like innerJoin but adds a left join instead of an inner join.

Adds a limit clause to the query.

A limit clause in a delete query is only supported by some dialects like MySQL.

Examples

Delete 5 oldest items in a table:

await db
  .deleteFrom('pet')
  .orderBy('created_at')
  .limit(5)
  .execute()
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The generated SQL (MySQL):

delete from `pet` order by `created_at` limit ?
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This can be used to add any additional SQL to the end of the query.

Examples

import { sql } from 'kysely'

await db.deleteFrom('person')
  .where('first_name', '=', 'John')
  .modifyEnd(sql`-- This is a comment`)
  .execute()
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The generated SQL (MySQL):

delete from `person`
where `first_name` = "John" -- This is a comment
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Allows you to return data from modified rows.

On supported databases like MS SQL Server (MSSQL), this method can be chained to insert, update, delete and merge queries to return data.

Also see the outputAll method.

Examples

Return one column:

const { id } = await db
  .insertInto('person')
  .output('inserted.id')
  .values({
    first_name: 'Jennifer',
    last_name: 'Aniston',
    gender: 'female',
  })
  .executeTakeFirstOrThrow()
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The generated SQL (MSSQL):

insert into "person" ("first_name", "last_name", "gender")
output "inserted"."id"
values (@1, @2, @3)
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Return multiple columns:

const { old_first_name, old_last_name, new_first_name, new_last_name } = await db
  .updateTable('person')
  .set({ first_name: 'John', last_name: 'Doe' })
  .output([
    'deleted.first_name as old_first_name',
    'deleted.last_name as old_last_name',
    'inserted.first_name as new_first_name',
    'inserted.last_name as new_last_name',
  ])
  .where('created_at', '<', new Date())
  .executeTakeFirstOrThrow()
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The generated SQL (MSSQL):

update "person"
set "first_name" = @1, "last_name" = @2
output "deleted"."first_name" as "old_first_name",
  "deleted"."last_name" as "old_last_name",
  "inserted"."first_name" as "new_first_name",
  "inserted"."last_name" as "new_last_name"
where "created_at" < @3
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Return arbitrary expressions:

import { sql } from 'kysely'

const { full_name } = await db
  .deleteFrom('person')
  .output((eb) => sql<string>`concat(${eb.ref('deleted.first_name')}, ' ', ${eb.ref('deleted.last_name')})`.as('full_name'))
  .where('created_at', '<', new Date())
  .executeTakeFirstOrThrow()
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The generated SQL (MSSQL):

delete from "person"
output concat("deleted"."first_name", ' ', "deleted"."last_name") as "full_name"
where "created_at" < @1
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Return the action performed on the row:

await db
  .mergeInto('person')
  .using('pet', 'pet.owner_id', 'person.id')
  .whenMatched()
  .thenDelete()
  .whenNotMatched()
  .thenInsertValues({
    first_name: 'John',
    last_name: 'Doe',
    gender: 'male'
  })
  .output([
    'inserted.id as inserted_id',
    'deleted.id as deleted_id',
  ])
  .execute()
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The generated SQL (MSSQL):

merge into "person"
using "pet" on "pet"."owner_id" = "person"."id"
when matched then delete
when not matched then
insert ("first_name", "last_name", "gender")
values (@1, @2, @3)
output "inserted"."id" as "inserted_id", "deleted"."id" as "deleted_id"
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Adds an output {prefix}.* to an insert/update/delete/merge query on databases that support output such as MS SQL Server (MSSQL).

Also see the output method.

Allows you to return data from modified rows.

On supported databases like PostgreSQL, this method can be chained to insert, update, delete and merge queries to return data.

Note that on SQLite you need to give aliases for the expressions to avoid this bug in SQLite. For example .returning('id as id').

Also see the returningAll method.

Examples

Return one column:

const { id } = await db
  .insertInto('person')
  .values({
    first_name: 'Jennifer',
    last_name: 'Aniston'
  })
  .returning('id')
  .executeTakeFirstOrThrow()
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Return multiple columns:

const { id, last_name } = await db
  .insertInto('person')
  .values({
    first_name: 'Jennifer',
    last_name: 'Aniston'
  })
  .returning(['id', 'last_name'])
  .executeTakeFirstOrThrow()
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Return arbitrary expressions:

import { sql } from 'kysely'

const { id, full_name, first_pet_id } = await db
  .insertInto('person')
  .values({
    first_name: 'Jennifer',
    last_name: 'Aniston'
  })
  .returning((eb) => [
    'id as id',
    sql<string>`concat(first_name, ' ', last_name)`.as('full_name'),
    eb.selectFrom('pet').select('pet.id').limit(1).as('first_pet_id')
  ])
  .executeTakeFirstOrThrow()
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Adds returning * or returning table.* clause to the query.

Examples

Return all columns.

const pets = await db
  .deleteFrom('pet')
  .returningAll()
  .execute()
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The generated SQL (PostgreSQL)

delete from "pet" returning *
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Return all columns from all tables

const result = await db
  .deleteFrom('toy')
  .using(['pet', 'person'])
  .whereRef('toy.pet_id', '=', 'pet.id')
  .whereRef('pet.owner_id', '=', 'person.id')
  .where('person.first_name', '=', 'Zoro')
  .returningAll()
  .execute()
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The generated SQL (PostgreSQL)

delete from "toy"
using "pet", "person"
where "toy"."pet_id" = "pet"."id"
and "pet"."owner_id" = "person"."id"
and "person"."first_name" = $1
returning *
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Return all columns from a single table.

const result = await db
  .deleteFrom('toy')
  .using(['pet', 'person'])
  .whereRef('toy.pet_id', '=', 'pet.id')
  .whereRef('pet.owner_id', '=', 'person.id')
  .where('person.first_name', '=', 'Itachi')
  .returningAll('pet')
  .execute()
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The generated SQL (PostgreSQL)

delete from "toy"
using "pet", "person"
where "toy"."pet_id" = "pet"."id"
and "pet"."owner_id" = "person"."id"
and "person"."first_name" = $1
returning "pet".*
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Return all columns from multiple tables.

const result = await db
  .deleteFrom('toy')
  .using(['pet', 'person'])
  .whereRef('toy.pet_id', '=', 'pet.id')
  .whereRef('pet.owner_id', '=', 'person.id')
  .where('person.first_name', '=', 'Luffy')
  .returningAll(['toy', 'pet'])
  .execute()
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The generated SQL (PostgreSQL)

delete from "toy"
using "pet", "person"
where "toy"."pet_id" = "pet"."id"
and "pet"."owner_id" = "person"."id"
and "person"."first_name" = $1
returning "toy".*, "pet".*
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Adds returning * or returning table.* clause to the query.

Examples

Return all columns.

const pets = await db
  .deleteFrom('pet')
  .returningAll()
  .execute()
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The generated SQL (PostgreSQL)

delete from "pet" returning *
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Return all columns from all tables

const result = await db
  .deleteFrom('toy')
  .using(['pet', 'person'])
  .whereRef('toy.pet_id', '=', 'pet.id')
  .whereRef('pet.owner_id', '=', 'person.id')
  .where('person.first_name', '=', 'Zoro')
  .returningAll()
  .execute()
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The generated SQL (PostgreSQL)

delete from "toy"
using "pet", "person"
where "toy"."pet_id" = "pet"."id"
and "pet"."owner_id" = "person"."id"
and "person"."first_name" = $1
returning *
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Return all columns from a single table.

const result = await db
  .deleteFrom('toy')
  .using(['pet', 'person'])
  .whereRef('toy.pet_id', '=', 'pet.id')
  .whereRef('pet.owner_id', '=', 'person.id')
  .where('person.first_name', '=', 'Itachi')
  .returningAll('pet')
  .execute()
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The generated SQL (PostgreSQL)

delete from "toy"
using "pet", "person"
where "toy"."pet_id" = "pet"."id"
and "pet"."owner_id" = "person"."id"
and "person"."first_name" = $1
returning "pet".*
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Return all columns from multiple tables.

const result = await db
  .deleteFrom('toy')
  .using(['pet', 'person'])
  .whereRef('toy.pet_id', '=', 'pet.id')
  .whereRef('pet.owner_id', '=', 'person.id')
  .where('person.first_name', '=', 'Luffy')
  .returningAll(['toy', 'pet'])
  .execute()
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The generated SQL (PostgreSQL)

delete from "toy"
using "pet", "person"
where "toy"."pet_id" = "pet"."id"
and "pet"."owner_id" = "person"."id"
and "person"."first_name" = $1
returning "toy".*, "pet".*
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Adds returning * or returning table.* clause to the query.

Examples

Return all columns.

const pets = await db
  .deleteFrom('pet')
  .returningAll()
  .execute()
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The generated SQL (PostgreSQL)

delete from "pet" returning *
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Return all columns from all tables

const result = await db
  .deleteFrom('toy')
  .using(['pet', 'person'])
  .whereRef('toy.pet_id', '=', 'pet.id')
  .whereRef('pet.owner_id', '=', 'person.id')
  .where('person.first_name', '=', 'Zoro')
  .returningAll()
  .execute()
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The generated SQL (PostgreSQL)

delete from "toy"
using "pet", "person"
where "toy"."pet_id" = "pet"."id"
and "pet"."owner_id" = "person"."id"
and "person"."first_name" = $1
returning *
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Return all columns from a single table.

const result = await db
  .deleteFrom('toy')
  .using(['pet', 'person'])
  .whereRef('toy.pet_id', '=', 'pet.id')
  .whereRef('pet.owner_id', '=', 'person.id')
  .where('person.first_name', '=', 'Itachi')
  .returningAll('pet')
  .execute()
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The generated SQL (PostgreSQL)

delete from "toy"
using "pet", "person"
where "toy"."pet_id" = "pet"."id"
and "pet"."owner_id" = "person"."id"
and "person"."first_name" = $1
returning "pet".*
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Return all columns from multiple tables.

const result = await db
  .deleteFrom('toy')
  .using(['pet', 'person'])
  .whereRef('toy.pet_id', '=', 'pet.id')
  .whereRef('pet.owner_id', '=', 'person.id')
  .where('person.first_name', '=', 'Luffy')
  .returningAll(['toy', 'pet'])
  .execute()
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The generated SQL (PostgreSQL)

delete from "toy"
using "pet", "person"
where "toy"."pet_id" = "pet"."id"
and "pet"."owner_id" = "person"."id"
and "person"."first_name" = $1
returning "toy".*, "pet".*
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Just like innerJoin but adds a right join instead of an inner join.

Just like innerJoin but adds a right join instead of an inner join.

Executes the query and streams the rows.

The optional argument chunkSize defines how many rows to fetch from the database at a time. It only affects some dialects like PostgreSQL that support it.

Examples

const stream = db
  .selectFrom('person')
  .select(['first_name', 'last_name'])
  .where('gender', '=', 'other')
  .stream()

for await (const person of stream) {
  console.log(person.first_name)

  if (person.last_name === 'Something') {
    // Breaking or returning before the stream has ended will release
    // the database connection and invalidate the stream.
    break
  }
}
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