Difference between revisions of "NULL Predicate"
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==Purpose== | ==Purpose== | ||
Special predicate | Special predicate | ||
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==Syntax== | ==Syntax== | ||
<expression> IS [NOT] NULL | <expression> IS [NOT] NULL | ||
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==See Also== | ==See Also== | ||
[[SQL INSERT|INSERT]], [[SQL Predicates|PREDICATES]], [[SQL SELECT|SELECT]], [[SQL UPDATE|UPDATE]] | [[SQL INSERT|INSERT]], [[SQL Predicates|PREDICATES]], [[SQL SELECT|SELECT]], [[SQL UPDATE|UPDATE]] | ||
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==Description== | ==Description== | ||
NULL is a special predicate to evaluate whether the specified <expression> is NULL. The optional NOT can be used to evaluate whether the specified <expression> is not NULL. | NULL is a special predicate to evaluate whether the specified <expression> is NULL. The optional NOT can be used to evaluate whether the specified <expression> is not NULL. | ||
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==Example== | ==Example== | ||
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</code> | </code> | ||
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[[Category:Documentation]] | [[Category:Documentation]] | ||
[[Category:SQL]] | [[Category:SQL]] | ||
Latest revision as of 08:11, 7 December 2012
Contents
Purpose
Special predicate
Syntax
<expression> IS [NOT] NULL
See Also
INSERT, PREDICATES, SELECT, UPDATE
Description
NULL is a special predicate to evaluate whether the specified <expression> is NULL. The optional NOT can be used to evaluate whether the specified <expression> is not NULL.
Example
SELECT name, address, balance, cost*1.15; FROM accounts; WHERE paid_date < date() AND ord_value IS NULL; ORDER BY name, paid_date
