What i want may seem simple but i have been at it for hours trying to get it to work and searching the internet for answers.

What i have been trying, and failing at doing, is taking X minuets from a time selected from a database (which is in the format DateTime in the database). Then after taking X minuets, use the new time to select something else from a database, base on the new time (Which is also in the format of DateTime in the datbase).

Any help would be much appreciated.

Following query will add 15 minutes to col2 and then compare new time with col1.
col1 and col2 must be datetime type column.

select * from mytable 
where col_1_datetime= date_add(col_2_datetime ,interval 15 minute)

Thanks for your reply. From that i found this function which works great:

WHERE Date>DATE_SUB('$UserLastCommentDate', INTERVAL 15 MINUTE)