On Sun, Jun 19, 2011 at 10:45:12AM +0800, lover boi wrote: > In the following statement, does the custom function get executed twice? > > SELECT > MY_FUNCTION(...), > CASE WHEN MY_FUNCTION(...) = '...' THEN '...' ELSE '...' END Yes > If so, is there a way I can make it execute once? I tried this but it gave me a "Column my_function does not exist" error. > > SELECT > > MY_FUNCTION(...) AS my_function, > > CASE WHEN my_function = '...' THEN '...' ELSE '...' END You almost had it right, there is another syntax for CASE: CASE MY_FUNCTION(...) WHEN 'foo' THEN ... WHEN 'bar' THEN ... ELSE ... END; http://www.postgresql.org/docs/8.4/static/functions-conditional.html Have a nice day, -- Martijn van Oosterhout <kleptog@xxxxxxxxx> http://svana.org/kleptog/ > Patriotism is when love of your own people comes first; nationalism, > when hate for people other than your own comes first. > - Charles de Gaulle
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