1.定位执行效率比较低的sql语句
1) mysql> desc select * from t1\G;
2) mysql> explain select * from t1\G;
mysql> desc select * from t1\G;
*************************** 1. row ***************************
id: 1
select_type: SIMPLE
table: t1
type: ALL
possible_keys: NULL
key: NULL
key_len: NULL
ref: NULL
rows: 7
Extra: NULL
1 row in set (0.00 sec)