Re: Auomatic numbering, replacing nulls and IF

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От Ian Harding
Тема Re: Auomatic numbering, replacing nulls and IF
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Msg-id sc98426c.029@mail.tpchd.org
обсуждение исходный текст
Ответ на Auomatic numbering, replacing nulls and IF  ("Pestilence" <me@work.com>)
Список pgsql-general
ISNULL (T-SQL)
Replaces NULL with the specified replacement value.

Syntax
ISNULL(check_expression, replacement_value)

Arguments
check_expression
Is the expression to be checked for NULL. check_expression can be of any type.
replacement_value
Is the expression to be returned if check_expression is NULL. replacement_value must have the same type as
check_expresssion. 
Return Types
Returns the same type as check_expression.

Remarks
The value of check_expression is returned if it is not NULL; otherwise, replacement_value is returned.


Ian A. Harding
Programmer/Analyst II
Tacoma-Pierce County Health Department
(253) 798-3549
mailto: iharding@tpchd.org

>>> Thomas Lockhart <thomas@fourpalms.org> 03/20/02 07:14AM >>>
...
> 2) The ISNULL function in both Oracle and MS-SQL takes 2 numbers and returns
> the second if the first is null, otherwise it returns the first. ISNULL in
> Postgres seems to be something quite different. Before I go writing my own
> function to do it, is there one already?

Look at COALESCE(). Does ISNULL() actually do something different in
Oracle and M$SQL? I'm curious because our definition conforms to the
SQL9x standard, and those databases claim to generally conform also.

                           - Thomas

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