no optimization?
Posted by:
Uwe
Date: May 22, 2006 05:47AM
Hello
Since MySQL 4.1 it's possible (but undocumented?) to use a syntax like:
SELECT * FROM tbl WHERE (field1, field2) = (val1, val2)
SELECT * FROM tbl WHERE (field1, field2) IN ((val1, val2), (val3, val4), ...)
Unfortunately this type of query results in a full table scan in both MySQL 4.1 and 5.0 even if field1 or field1+field2 are keys. Force Index (field1) doesn't work either.
Is this a bug or is it just an unofficial feature not built into the optimizer yet?
Uwe
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no optimization?
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