# delete

DELETE

DELETE

7

SQL - Language Statements

DELETE

delete rows of a table

\[ WITH \[ RECURSIVE \]

with_query

\[, ...\] \] DELETE FROM \[ ONLY \]

table_name

\[ \* \] \[ \[ AS \]

alias

\] \[ USING

from_item

\[, ...\] \] \[ WHERE

condition

\| WHERE CURRENT OF

cursor_name

\] \[ RETURNING \[ WITH ( { OLD \| NEW } AS

output_alias

\[, ...\] ) \] { \* \|

output_expression

\[ \[ AS \]

output_name

\] } \[, ...\] \]

# Description

`DELETE` deletes rows that satisfy the `WHERE` clause from the specified table. If the `WHERE` clause is absent, the effect is to delete all rows in the table. The result is a valid, but empty table.

> [!TIP]
> [`TRUNCATE`](#sql-truncate) provides a faster mechanism to remove all rows from a table.

There are two ways to delete rows in a table using information contained in other tables in the database: using sub-selects, or specifying additional tables in the `USING` clause. Which technique is more appropriate depends on the specific circumstances.

The optional `RETURNING` clause causes `DELETE` to compute and return value(s) based on each row actually deleted. Any expression using the table's columns, and/or columns of other tables mentioned in `USING`, can be computed. The syntax of the `RETURNING` list is identical to that of the output list of `SELECT`.

You must have the `DELETE` privilege on the table to delete from it, as well as the `SELECT` privilege for any table in the `USING` clause or whose values are read in the \<condition\>.

# Parameters

\<with_query\>  
The `WITH` clause allows you to specify one or more subqueries that can be referenced by name in the `DELETE` query. See [???](#queries-with) and [???](#sql-select) for details.

\<table_name\>  
The name (optionally schema-qualified) of the table to delete rows from. If `ONLY` is specified before the table name, matching rows are deleted from the named table only. If `ONLY` is not specified, matching rows are also deleted from any tables inheriting from the named table. Optionally, `*` can be specified after the table name to explicitly indicate that descendant tables are included.

\<alias\>  
A substitute name for the target table. When an alias is provided, it completely hides the actual name of the table. For example, given `DELETE FROM foo AS f`, the remainder of the `DELETE` statement must refer to this table as `f` not `foo`.

\<from_item\>  
A table expression allowing columns from other tables to appear in the `WHERE` condition. This uses the same syntax as the [`FROM`](#sql-from) clause of a `SELECT` statement; for example, an alias for the table name can be specified. Do not repeat the target table as a \<from_item\> unless you wish to set up a self-join (in which case it must appear with an alias in the \<from_item\>).

\<condition\>  
An expression that returns a value of type `boolean`. Only rows for which this expression returns `true` will be deleted.

\<cursor_name\>  
The name of the cursor to use in a `WHERE CURRENT OF` condition. The row to be deleted is the one most recently fetched from this cursor. The cursor must be a non-grouping query on the `DELETE`'s target table. Note that `WHERE CURRENT OF` cannot be specified together with a Boolean condition. See [???](#sql-declare) for more information about using cursors with `WHERE CURRENT OF`.

\<output_alias\>  
An optional substitute name for `OLD` or `NEW` rows in the `RETURNING` list.

By default, old values from the target table can be returned by writing `OLD.column_name` or `OLD.*`, and new values can be returned by writing `NEW.column_name` or `NEW.*`. When an alias is provided, these names are hidden and the old or new rows must be referred to using the alias. For example `RETURNING WITH (OLD AS o, NEW AS n) o.*, n.*`.

\<output_expression\>  
An expression to be computed and returned by the `DELETE` command after each row is deleted. The expression can use any column names of the table named by \<table_name\> or table(s) listed in `USING`. Write `*` to return all columns.

A column name or `*` may be qualified using `OLD` or `NEW`, or the corresponding \<output_alias\> for `OLD` or `NEW`, to cause old or new values to be returned. An unqualified column name, or `*`, or a column name or `*` qualified using the target table name or alias will return old values.

For a simple `DELETE`, all new values will be `NULL`. However, if an `ON DELETE` rule causes an `INSERT` or `UPDATE` to be executed instead, the new values may be non-`NULL`.

\<output_name\>  
A name to use for a returned column.

# Outputs

On successful completion, a `DELETE` command returns a command tag of the form

    DELETE count

The \<count\> is the number of rows deleted. Note that the number may be less than the number of rows that matched the \<condition\> when deletes were suppressed by a `BEFORE DELETE` trigger. If \<count\> is 0, no rows were deleted by the query (this is not considered an error).

If the `DELETE` command contains a `RETURNING` clause, the result will be similar to that of a `SELECT` statement containing the columns and values defined in the `RETURNING` list, computed over the row(s) deleted by the command.

# Notes

PostgreSQL lets you reference columns of other tables in the `WHERE` condition by specifying the other tables in the `USING` clause. For example, to delete all films produced by a given producer, one can do:

    DELETE FROM films USING producers
      WHERE producer_id = producers.id AND producers.name = 'foo';

What is essentially happening here is a join between films and producers, with all successfully joined films rows being marked for deletion. This syntax is not standard. A more standard way to do it is:

    DELETE FROM films
      WHERE producer_id IN (SELECT id FROM producers WHERE name = 'foo');

In some cases the join style is easier to write or faster to execute than the sub-select style.

# Examples

Delete all films but musicals:

    DELETE FROM films WHERE kind <> 'Musical';

Clear the table films:

    DELETE FROM films;

Delete completed tasks, returning full details of the deleted rows:

    DELETE FROM tasks WHERE status = 'DONE' RETURNING *;

Delete the row of tasks on which the cursor `c_tasks` is currently positioned:

    DELETE FROM tasks WHERE CURRENT OF c_tasks;

While there is no `LIMIT` clause for `DELETE`, it is possible to get a similar effect using the same method described in [the documentation of `UPDATE`](#update-limit):

    WITH delete_batch AS (
      SELECT l.ctid FROM user_logs AS l
        WHERE l.status = 'archived'
        ORDER BY l.creation_date
        FOR UPDATE
        LIMIT 10000
    )
    DELETE FROM user_logs AS dl
      USING delete_batch AS del
      WHERE dl.ctid = del.ctid;

This use of ctid is only safe because the query is repeatedly run, avoiding the problem of changed ctids.

# Compatibility

This command conforms to the SQL standard, except that the `USING` and `RETURNING` clauses are PostgreSQL extensions, as is the ability to use `WITH` with `DELETE`.

# See Also