Re: Function use in query - Mailing list pgsql-general

From David Johnston
Subject Re: Function use in query
Date
Msg-id 1370466844313-5758066.post@n5.nabble.com
Whole thread Raw
In response to Function use in query  (Ioana Danes <ioanasoftware@yahoo.ca>)
Responses Re: Function use in query  (Ioana Danes <ioanasoftware@yahoo.ca>)
List pgsql-general
Ioana Danes wrote
> Hi All,
> Is there any similar syntax that only invokes the procedure once and
> returns all the columns?

Generic, adapt to fit your needs.


WITH func_call AS (
SELECT function_call(...) AS func_out_col
)
SELECT (func_out_col).*
FROM func_call;

Basically you have to execute the function call and leave the result as a
single column (a row type).  Then, in another layer of the query, you expand
that single column into its components using "*".  Because you are expanding
a column and not a table you must put the column name in "()" - otherwise
the parser thinks "func_out_col" is a table and errors out.

This all definitely applies to 9.2 and earlier.  9.3 (with lateral) may
behave differently...

David J.




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