mysql命令行开启慢查询日志的方法：执行【set global slow_query_log='on';】语句即可开启。通过执行【show variables like %slow%;】语句可以检查慢查询日志是否已开启。
具体方法：
（推荐教程：mysql教程）
查看一下默认慢查询的时间10秒
mysql> show variables like "%long%"; +-----------------+-----------+| variable_name | value |+-----------------+-----------+| long_query_time | 10.000000 |+-----------------+-----------+1 row in set (0.00 sec)
设置成3秒，加上global,退出再次进入生效
mysql> set global long_query_time=3; query ok, 0 rows affected (0.00 sec)
查看一下慢查询是不是已经开启
mysql> show variables like "%slow%"; +---------------------+---------------------------------+| variable_name | value |+---------------------+---------------------------------+| log_slow_queries | off || slow_launch_time | 2 || slow_query_log | off || slow_query_log_file | /usr/local/mysql/mysql-slow.log |+---------------------+---------------------------------+4 rows in set (0.00 sec)
启用慢查询
mysql> set global slow_query_log='on'; query ok, 0 rows affected (0.28 sec)
查看是否已经开启
mysql> show variables like "%slow%"; +---------------------+---------------------------------+| variable_name | value |+---------------------+---------------------------------+| log_slow_queries | on || slow_launch_time | 2 || slow_query_log | on || slow_query_log_file | /usr/local/mysql/mysql-slow.log |+---------------------+---------------------------------+4 rows in set (0.00 sec)
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以上就是mysql命令行怎么开启慢查询日志的详细内容。