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select t.json,t.json->"$.form" from table t where json_contains(t.json->"$.form","\"7ca045406eb24d25a0a3f8bf64107f55\"")

1.sql语句select (@i:=@i+1) _index,a.* from a,(select @i:=0) vars2.结果

1.表结构CREATE TABLE `tree` ( `id` int(11) NOT NULL AUTO_INCREMENT, `pid` int(11) DEFAULT NULL, `tname` varchar(255) DEFAULT NULL, PRIMARY KEY (`id`)) ENGINE=InnoDB AUTO_INCREMENT=20 DEFAULT ...

insert into c (a_id,b_id) select 2, b_id from c where a_id=1

update customer aset a.name = case a.idwhen 41 then "name41"when 42 then "name42"else a.nameend

1.表结构DROP TABLE IF EXISTS `tree`;CREATE TABLE `tree` ( `id` int(11) NOT NULL AUTO_INCREMENT, `pid` int(11) DEFAULT NULL, `pids` varchar(255) DEFAULT NULL, `tname` varchar(255) DEFAULT NULL...

1.表结构及测试数据DROP TABLE IF EXISTS `tree`;CREATE TABLE `tree` ( `id` int(11) NOT NULL AUTO_INCREMENT, `pid` int(11) DEFAULT NULL, `tname` varchar(255) DEFAULT NULL, PRIMARY KEY (`id`)) ENGINE...

1关键字begin打开事务，中间执行相关sql语句，最后commit提交完成事务mysql> begin;Query OK, 0 rows affected (0.00 sec)mysql> insert into student (stu_id,name,c_id) values ('100','soul','1');Query OK, 1 row affected (...

1.读未提交打开a事务更新一条数据打开b事务查询这条数据此时a事务回滚b再次查询 数据与上次不一致，此为脏读2.读已提交打开a事务，修改数据，未提交打开事务b，查找同一条数据，数据并未与a事务中未提交的数据保持一致，解决脏读问题此时事务a提交事务b再查一次，前后两次数据不一致，此为不可重复读3.可重复读打开事务a，执行更新...

1.查询student表mysql> select * from student;+--------+------+------+| stu_id | name | c_id |+--------+------+------+| 001 | jim | 1 || 002 | tom | 2 |+--------+------+------+2 ...

alert table user add name varchar(100) 

1.选择mysql库use mysql;2.修改user表GRANT ALL PRIVILEGES ON *.* TO 'root'@'%'IDENTIFIED BY '123456' WITH GRANT OPTION;3.刷新flush privileges; 

1.表结构CREATE TABLE `jiami` ( `id` int(11) NOT NULL AUTO_INCREMENT, `name` blob, PRIMARY KEY (`id`)) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=utf8;2.加密insert into jiami (name) value...

1.新建数据库CREATE DATABASE db DEFAULT CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci；2.选择dbuse db;3.导入source /home/db.sql; 

1.表结构CREATE TABLE `timer` ( `id` int(11) NOT NULL AUTO_INCREMENT, `date` datetime DEFAULT NULL, PRIMARY KEY (`id`)) ENGINE=InnoDB AUTO_INCREMENT=22 DEFAULT CHARSET=utf8;2.创建定时器CREATE EV...

1.表结构CREATE TABLE `employ` ( `id` varchar(255) NOT NULL, `name` varchar(255) DEFAULT NULL, `companyid` varchar(255) DEFAULT NULL, PRIMARY KEY (`id`), UNIQUE KEY `test` (`name`,`companyid`...