Interface RawBuilder<O>

An instance of this class can be used to create raw SQL snippets or queries.

You shouldn't need to create RawBuilder instances directly. Instead you should use the sql template tag.

Type Parameters

  • O



  • get expressionType(): undefined | T
  • All expressions need to have this getter for complicated type-related reasons. Simply add this getter for your expression and always return undefined from it:

    class SomeExpression<T> implements Expression<T> {
    get expressionType(): Tundefined {
    return undefined

    The getter is needed to make the expression assignable to another expression only if the types T are assignable. Without this property (or some other property that references T), you could assing Expression<string> to Expression<number>.

    Returns undefined | T


  • Omit null from the expression's type.

    This function can be useful in cases where you know an expression can't be null, but Kysely is unable to infer it.

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

    Returns RawBuilder<Exclude<O, null>>

  • Returns an aliased version of the SQL expression.

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

    const result = await db
    sql<string>`concat(first_name, ' ', last_name)`.as('full_name')

    // `full_name: string` field exists in the result type.

    The generated SQL (PostgreSQL):

    select concat(first_name, ' ', last_name) as "full_name"
    from "person"

    You can also pass in a raw SQL snippet but in that case you must provide the alias as the only type argument:

    const values = sql<{ a: number, b: string }>`(values (1, 'foo'))`

    // The alias is `t(a, b)` which specifies the column names
    // in addition to the table name. We must tell kysely that
    // columns of the table can be referenced through `t`
    // by providing an explicit type argument.
    const aliasedValues =<'t'>(sql`t(a, b)`)

    await db
    .columns(['first_name', 'last_name'])
    db.selectFrom(aliasedValues).select(['t.a', 't.b'])

    The generated SQL (PostgreSQL):

    insert into "person" ("first_name", "last_name")
    from (values (1, 'foo')) as t(a, b)
    select "t"."a", "t"."b"

    Type Parameters

    • A extends string


    • alias: A

    Returns AliasedRawBuilder<O, A>

  • Type Parameters

    • A extends string


    Returns AliasedRawBuilder<O, A>

  • 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()

    Returns RawNode

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