Checking for CONCAT() in WHERE clause

anjanesh · #1 (**permalink**) 01-06-06, 06:55

Any way to get this working ?

Code:

SELECT *,
CONCAT(`field1`, `field2`,`field3`,`field4`,`field5`) AS Uniq
FROM `table1` WHERE Uniq = 'somevalue'

Neither does this work too.

Code:

SELECT *,
CONCAT(`field1`, `field2`,`field3`,`field4`,`field5`) AS tbl1.Uniq
FROM `table1` tbl1 WHERE tbl1.Uniq = 'somevalue'

yellowmarker · #2 (**permalink**) 01-07-06, 11:49

It is not possible to use a field alias in the WHERE clause. Your solution would be either to check the value each field in the WHERE clause, or possibly to use an IF condition in your SELECT clause. If neither of these alternatives are appropriate you might decide to make use of a temporary table.

see http://dev.mysql.com/doc/refman/5.0/en/select.html

"The alias is used as the expression's column name and can be used in GROUP BY, ORDER BY, or HAVING clauses."

"It is not allowable to use a column alias in a WHERE clause, because the column value might not yet be determined when the WHERE clause is executed."

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