[sql] SQL query for getting data for last 3 months

How can you get today's date and convert it to 01/mm /yyyy format and get data from the table with delivery month 3 months ago? Table already contains delivery month as 01/mm/yyyy.

Latest Versions of mysql don't support DATEADD instead use the syntax

DATE_ADD(date,INTERVAL expr type)

To get the last 3 months data use,

DATE_ADD(NOW(),INTERVAL -90 DAY) 
DATE_ADD(NOW(), INTERVAL -3 MONTH)

Last 3 months

SELECT DATEADD(dd,DATEDIFF(dd,0,DATEADD(mm,-3,GETDATE())),0)

Today

SELECT DATEADD(dd,DATEDIFF(dd,0,GETDATE()),0)

I'd use datediff, and not care about format conversions:

SELECT *
FROM   mytable
WHERE  DATEDIFF(MONTH, my_date_column, GETDATE()) <= 3