[Your question has nothing to do with the MyISAM storage engine. Please pick a more appropriate forum next time]
Anthony Willard wrote:
> I'm trying to summarize some data and use the "WITH ROLLUP" clause to generate the totals. In
> my "SELECT", I'm trying to use a "CASE" statement to replace the "NULL" value produced by the "WITH
> ROLLUP" with text indicating that this row represents a break total for this column.
From
http://dev.mysql.com/doc/refman/5.0/en/group-by-modifiers.html:
Because the NULL values in the super-aggregate rows are placed into the result set at such a late stage in query processing, you cannot test them as NULL values within the query itself. For example, you cannot add HAVING product IS NULL to the query to eliminate from the output all but the super-aggregate rows.
On the other hand, the NULL values do appear as NULL on the client side and can be tested as such using any MySQL client programming interface.
--
felix
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Edited 1 time(s). Last edit at 11/15/2005 12:32PM by Felix Geerinckx.