我们有时候须要查看mysql的运行历史，比方我们做sql优化的时候，起码要知道运行的sql是什么。框架通常会帮我们拼装sql，所以在程序中不一定能够打印出sql，这个时候就须要mysql的general
log了。
查看设置mysql genneral log
show VARIABLES like '%general_log%';
set GLOBAL general_log = off;// on-打开; off-关闭
general_log ON
general_log_file /var/log/mysql/query.log
使用mysql general log
tail -f /path/to/log/query.log | grep yourtable
13518 Prepare SELECT count(*) AS `count` FROM `babysitter_tips` WHERE (tip_type = '1') AND (is_enable = 1) AND (is_tip = 2)
13518 Query DESCRIBE `babysitter_tips`
13518 Close stmt
13518 Prepare SELECT `babysitter_tips`.* FROM `babysitter_tips` WHERE (tip_type = '1') AND (is_enable = 1) AND (is_tip = 2) ORDER BY `created_time` desc LIMIT 5
13518 Reset stmt
13518 Close stmt
13518 Prepare SELECT count(*) AS `count` FROM `babysitter_tips` WHERE (tip_type = '1') AND (is_enable = 1) AND (is_tip = 2) AND (tip_id > 15440)
13518 Close stmt
13518 Prepare SELECT count(*) AS `count` FROM `babysitter_tips` WHERE (tip_type = '3') AND (is_enable = 1) AND (is_tip = 2)
13518 Query DESCRIBE `babysitter_tips`
13518 Close stmt
13518 Prepare SELECT `babysitter_tips`.* FROM `babysitter_tips` WHERE (tip_type = '3') AND (is_enable = 1) AND (is_tip = 2) ORDER BY `created_time` desc LIMIT 5
13518 Reset stmt
13518 Close stmt
13518 Prepare SELECT count(*) AS `count` FROM `babysitter_tips` WHERE (tip_type = '3') AND (is_enable = 1) AND (is_tip = 2) AND (tip_id > '')
13518 Close stmt
13518 Prepare SELECT count(*) AS `count` FROM `babysitter_tips` WHERE (tip_type = '2') AND (is_enable = 1) AND (is_tip = 2)
13518 Query DESCRIBE `babysitter_tips`
13518 Close stmt
13518 Prepare SELECT `babysitter_tips`.* FROM `babysitter_tips` WHERE (tip_type = '2') AND (is_enable = 1) AND (is_tip = 2) ORDER BY `created_time` desc LIMIT 5
13518 Reset stmt
13518 Close stmt清理mysql general log
general log会比較大，所以默认市关闭的，所以最好须要的时候打开，随手关闭。假设发现query.log过大。能够手动删除。在general log打开的情况下，query.log文件相似于mysql表的lock情况，不同意改动和删除。关闭general log就能够操作了。