MySQL의 IN() v.s. EXISTS v.s. INNER JOIN 성능 비교

http://mysqlguru.github.io/mysql/2014/05/28/mysql-in-vs-exists-vs-inner-join.html

추가로 

MySQL INNER JOIN v.s EXISTS 성능 비교

http://mysqlguru.github.io/mysql/2014/05/30/mysql-inner-join-vs-exists.html