Question

I have a database that stores a large number of codes, these codes are used to validate submission of a form. When ever i run the following query i get zero rows back

SELECT * FROM `codes` WHERE `voucher` = 'JTBLYNQ9HA'

but when i run the following query it bring back the single row with the code in it.

SELECT * FROM  `codes` WHERE  `voucher` LIKE CONVERT( _utf8 '%JTBLYNQ9HA%' USING latin1 ) COLLATE latin1_swedish_ci LIMIT 0 , 30

What am i doing wrong which causes the first query to fail or should is it best practise to use the second query?

Thanks for the help

Answer 1

The two queries are not equivalent. The first one is looking for a code whose voucher is exactly “JTBLYNQ9HA”, the second one is looking for a code whose voucher contains that string (for instance, “ABCDEFGJTBLYNQ9HAHIJKLM”).

The character set conversion and COLLATE are almost certainly irrelevant.