If you want to retrieve result based on today, this week or this month then you should visit the article to learn the mysql techniques.

This is a post about "SYSDATE()" and "NOW()" and "CURRENT_TIMESTAMP()" functions in MySQL.Firstly, note is that of these three, only "CURRENT_TIMESTAMP()" is part of the SQL Standard. "NOW()" happens to be an alias for "CURRENT_TIMESTAMP()" in MySQL.Secondly, note that replication does not work well with non-deterministic functions. And "hey, what time is it?" is non-deterministic. Ask it twice, with a second apart between asking, and both times you get different results (with at least second precision).You can start to see the problem here....but there's more....

Creating a MySQL-plugin that can be used to create a function which can in turn be used in stored procedures.