WordPress is most commonly use blogging platform that it used beyond the limit of blogs to the extend of CMS. Many highly traffic sites and e-commerce site use wordpress as in back end. Many times we need to monitor the server load and SQL queries running in wordpress in order to maintain the smoothness of websites. We know that poor and damaged performance is due to poorly designed database or SQL queries (for example, when the table does not have indices that the query can use or when the query uses unnecessary performance killers such as ORDER BY/GROUP BY).
If you are not familiar then i will also recommend you 13 useful wordPress SQL queries you wish you knew earlier and top five WordPress SQL queries.