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Windza
Yak Posting Veteran
61 Posts |
 Posted - 2008-12-15 : 14:58:14
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| Just curious why a column reference in a CASE condition is required in the GROUP BY clause even though it isn't in the SELECT list (at least as an output)... is there an obvious explanation or standard workaround?e.g.SELECTCASE WHEN column_name > 0THEN column_name2 ELSE NULL ENDFROMtable_nameGROUP BYcolumn_name2fails with the standard msg:Column 'column_name' is invalid in the select list because it is not contained in either an aggregate function or the GROUP BY clause.I understand the reasoning (I think anyway) behind the GROUP BY clause but cannot see why the above fails to work... the only way I can seem to bypass the issue is using something like the following:SELECTa.ColumnName2FROM (SELECT CASE WHEN column_name > 0 THEN column_name2 ELSE NULL END AS ColumnName2FROM table_name)aGROUP BY a.ColumnName2If someone has stumbled across this before and has some answers I would be most appreciative... I realise I'm probably just posing a typical newbie type question but any information is valued nonetheless...Cheers |
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hanbingl
Aged Yak Warrior
652 Posts |
Posted - 2008-12-15 : 15:46:06
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| group by CASE WHEN column_name > 0THEN column_name2 ELSE NULL END |
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Windza
Yak Posting Veteran
61 Posts |
Posted - 2008-12-15 : 16:06:03
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| Oh... that easy huh !O O*|* \__/ |
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CASE Condition required in GROUP BY Clause?