MySQL Performance Tuning Don't hide in function
Example
A common mistake is to hide an indexed column inside a function call. For example, this can't be helped by an index:
WHERE DATE(dt) = '2000-01-01'
Instead, given INDEX(dt) then these may use the index:
WHERE dt = '2000-01-01' -- if `dt` is datatype `DATE`
This works for DATE, DATETIME, TIMESTAMP, and even DATETIME(6) (microseconds):
WHERE dt >= '2000-01-01'
AND dt < '2000-01-01' + INTERVAL 1 DAY
