摘要:
SQL单行拆分多行 不需要自建自增的辅助表,Mysql自带help_topic可以使用; SELECT SUBSTRING_INDEX( SUBSTRING_INDEX( target_column, ',', b.help_topic_id + 1 ), ',', -1 ) AS coop_bra 阅读全文
摘要:
不重启mysql,查询执行时间超长的SQLID,kill show full processlist; select concat('KILL ',id,';') from information_schema.processlist where command='Query'; 阅读全文
摘要:
Mysql的各种JOIN 1、CROSS JOIN = JOIN,使用方式: SELECT * FROM table1 CROSS JOIN table2 ; SELECT * FROM table1 JOIN table2 SELECT * FROM table1,table2 2、INNER J 阅读全文