删除基于Mysql / PHP中的float列的行？

Question

This

DELETE FROM `z_ratings` 
WHERE `score` = '5.4' 
  AND `media_id` = '242' 
  AND `user_id` = '1'

will not delete the following row:

Can anybody explain why?

(I'm assuming the issue is with the float since both other columns are integers)

Answer 1

The problem is the floating point column. You can review the issues with this representation and comparisons. One place to start is the documentation .

Great, we know it doesn't work. More importantly, what can you do?

Probably the most accurate solution is to switch to decimal, say decimal(5, 1) for the column. Then, this shouldn't be a problem.

Alternatively, use abs() and difference for a fuzzy comparison:

abs(score - 3.4) < 0.0001