SELECT * FROM table1 USE INDEX (col1_index,col2_index) WHERE col1=1 AND col2=2 AND col3=3; SELECT * FROM table1 IGNORE INDEX (col3_index) WHERE col1=1 AND col2=2 AND col3=3;
1、http://dev.mysql.com/doc/refman/5.5/en/index-hints.html
2、https://en.wikipedia.org/wiki/Hint_(SQL)