Re: Problems with simple(?) query

[Michael T. Babcock]

Keith C. Ivey wrote:

On 11 Nov 2002, at 20:03, James Dyer wrote:

SELECT * FROM foo WHERE id2=1 AND id2=2 (for example),

I just get an empty set returned. An explain on the query gives an 'Impossible WHERE'
message.

Because it's impossible for id2 to be both 1 and 2. What were you expecting? Did you mean "id1 = 1 AND id2 = 2"? If not, you need to explain what records you're trying to get.

I've found that quite a few people I know misconstrue boolean values to mean the opposites of what they in fact do mean in queries as in "I want the record where ID is 1 and the record where it is 2" is not as written above, but in fact "WHERE ID2 IN (1, 2)" or "WHERE ID2 = 1 OR ID2 = 2". A logic course would fix most of these problems of course ...

--
Michael T. Babcock
C.T.O., FibreSpeed Ltd.
http://www.fibrespeed.net/~mbabcock



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