Question

I wrote this query and it is working fine, except in the month of FEB! for some reason because FEB has 28 days by using the INTERVAL 1 MONTH function it reads back into JAN also. and it should only read from start of FEB to END of FEB!

SELECT SUM(IF((`date` BETWEEN DATE_SUB('2013-02-28', INTERVAL 1 MONTH) AND '2013-02-28'), earnings, "null")) AS Rev0 
FROM table

Answer 1

Given any date, you can use this to get the first day of the month:

DATE_SUB('2013-02-28', INTERVAL DAY('2013-02-28')-1 DAY)

or also this:

CAST(DATE_FORMAT('2013-02-28' ,'%Y-%m-01') as DATE)

and for the last day, there’s a function already defined:

LAST_DAY('2013-02-28')

your query would then become:

SELECT
  SUM(IF((`date` BETWEEN DATE_SUB('2013-02-28', INTERVAL DAY('2013-02-28')-1 DAY)
          AND LAST_DAY('2013-02-28')), earnings, "null")) AS Rev0 
FROM table