Question

I have a table with this fields

id    sell_date   
a1    27/7/2012
a1    26/7/2012
a1    24/7/2012
a1    24/2/2012

I want a count of the months who has sells in a period of one year before the current date.
result

a1 = 2

Answer 1

You need the datediff() function:

select count(id) as N 
from table_name
where datediff(curdate(), sell_date) >= 365;

http://dev.mysql.com/doc/refman/5.1/en/date-and-time-functions.html#function_datediff
http://dev.mysql.com/doc/refman/5.1/en/date-and-time-functions.html#function_curdate