Jaa

DELETE FROM

  • Artikkeli

Applies to: check marked yes Databricks SQL check marked yes Databricks Runtime

Deletes the rows that match a predicate. When no predicate is provided, deletes all rows.

This statement is only supported for Delta Lake tables.

Syntax

DELETE FROM table_name [table_alias] [WHERE predicate]

Parameters

  • table_name

    Identifies an existing table. The name must not include a temporal specification.

    table_name must not be a foreign table.

  • table_alias

    Define an alias for the table. The alias must not include a column list.

  • WHERE

    Filter rows by predicate.

    The WHERE predicate supports subqueries, including IN, NOT IN, EXISTS, NOT EXISTS, and scalar subqueries. The following types of subqueries are not supported:

    • Nested subqueries, that is, an subquery inside another subquery
    • NOT IN subquery inside an OR, for example, a = 3 OR b NOT IN (SELECT c from t)

    In most cases, you can rewrite NOT IN subqueries using NOT EXISTS. We recommend using NOT EXISTS whenever possible, as DELETE with NOT IN subqueries can be slow.

Examples

> DELETE FROM events WHERE date < '2017-01-01'

> DELETE FROM all_events
   WHERE session_time < (SELECT min(session_time) FROM good_events)

> DELETE FROM orders AS t1
   WHERE EXISTS (SELECT oid FROM returned_orders WHERE t1.oid = oid)

> DELETE FROM events
   WHERE category NOT IN (SELECT category FROM events2 WHERE date > '2001-01-01')