mysql> select count(year='2006' or null) as '2006' ,count(year='2009' or null) as '2008' from y;
+------+------+
| 2006 | 2008 |
+------+------+
| 2 | 1 |
+------+------+
1 row in set (0.00 sec)
查看是否開啟慢查詢日志 show variables like 'slow_query_log'
設置沒有索引的記錄到慢查詢日志 set global log_queries_not_using_indexes=on
查看超過多長時間的sql進行記錄到慢查詢日志 show variables like 'long_query_time'
設置慢查詢的時間 set long_query_time=1
