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53 lines
1.7 KiB
Plaintext
53 lines
1.7 KiB
Plaintext
-----------------------
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OFFSET and FETCH clause
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-----------------------
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Function:
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SQL:2008 compliant equivalent for FIRST/SKIP, and an alternative for ROWS.
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The OFFSET clause specifies the number of rows to skip. The FETCH clause
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specifies the number of rows to fetch.
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OFFSET and FETCH can be applied independently on top-level and nested query
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expressions.
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Author:
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Mark Rotteveel <mrotteveel@users.sourceforge.net>
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Syntax rules:
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SELECT ... [ ORDER BY <expr_list> ]
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[ OFFSET <simple_value_expr> { ROW | ROWS } ]
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[ FETCH { FIRST | NEXT } [ <simple_value_expr> ] { ROW | ROWS } ONLY ]
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Where <simple_value_expr> is a (numeric) literal, a SQL parameter (?) or
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PSQL named parameter (:namedparameter).
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Scope:
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DSQL, PSQL
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Example(s):
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1. SELECT * FROM T1
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ORDER BY COL1
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OFFSET 10 ROWS
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2. SELECT * FROM T1
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ORDER BY COL1
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FETCH FIRST 10 ROWS ONLY
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3. SELECT * FROM (
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SELECT * FROM T1
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ORDER BY COL1 DESC
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OFFSET 1 ROW
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FETCH NEXT 10 ROWS ONLY
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) a
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ORDER BY a.COL1
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FETCH FIRST ROW ONLY
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Note(s):
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1. Firebird doesn't support the percentage FETCH defined in the SQL
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standard.
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2. Firebird doesn't support the FETCH ... WITH TIES defined in the SQL
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standard.
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3. The FIRST/SKIP and ROWS clause are non-standard alternatives.
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4. The OFFSET and/or FETCH clauses cannot be combined with ROWS or
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FIRST/SKIP on the same query expression.
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5. Expressions, column references, etc are not allowed within either clause.
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6. Contrary to the ROWS clause, OFFSET and FETCH are only available on
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SELECT statements. |