Re: If function available?

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От Josh Berkus
Тема Re: If function available?
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Msg-id web-510100@davinci.ethosmedia.com
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Ответ на If function available?  (Francisco Reyes <lists@natserv.com>)
Ответы Re: If function available?  (Francisco Reyes <lists@natserv.com>)
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Francisco,

> I tried it from the psql prompt and didn't work. Is there an IF or
> IIF function that can be used on a select query?

You want CASE, as in:

CASE WHEN field1 = 1 THEN NULL ELSE field1 END

See Postgresql.org --> Documentation --> SQL Commands --> SELECT for
more information, or consult your favorite SQL92 manual.

There are also several special functions for dealing with NULL output,
such as:

COALESCE(x,y,z) : returns first non-null value
NULLIF(x, y) : returns NULL if x = y

-Josh

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