Available in: DSQL, ESQL, PSQL
Description
Deletes rows from a database table (or from one or more tables underlying a view), depending on the WHERE and ROWS clauses.
Syntax
DELETE [TRANSACTION name] FROM {tablename | viewname} [[AS] alias] [WHERE {search-conditions | CURRENT OF cursorname}] [PLAN plan_items] [ORDER BY sort_items] [ROWS <m> [TO <n>]] <m>, <n> ::= Any expression evaluating to an integer.
Restrictions
Added in: 2.0
Description
COLLATE subclauses are now also supported for text BLOBs.
Example
delete from MyTable where NameBlob collate pt_br = 'João'
Added in: 2.0
Description
DELETE now allows an ORDER BY clause. This only makes sense in combination with ROWS, but is also valid without it.
Added in: 2.0
Description
DELETE now allows a PLAN clause, so users can optimize the operation manually.
Changed in: 2.0
Description
If you give a table or view an alias in a Firebird 2.0 or above statement, you must use the alias, not the table name, if you want to qualify fields from that relation.
Examples
Correct usage:
delete from Cities where name starting 'Alex' delete from Cities where Cities.name starting 'Alex' delete from Cities C where name starting 'Alex' delete from Cities C where C.name starting 'Alex'
No longer possible:
delete from Cities C where Cities.name starting 'Alex'
Added in: 2.0
Description
Limits the amount of rows deleted to a specified number or range.
Syntax
ROWS <m> [TO <n>] <m>, <n> ::= Any expression evaluating to an integer.
With a single argument m, the deletion is limited to the first m rows of the dataset defined by the table or view and the optional WHERE and ORDER BY clauses.
Points to note:
With two arguments m and n, the deletion is limited to rows m to n inclusively. Row numbers are 1-based.
Points to note when using two arguments:
ROWS can also be used with the SELECT and UPDATE statements.