1.mysql update 语句: update user set name = 'xiaoming',age = 18 where uid = 3000; 更新记录时update操作也不需要写table关键字,像insert into一样,不需要写table关键字,直接写表名即可 2.mysql insert 语句: insert into user(uid,age,name,address) values(1000,18,'xiaohong','hunanyiyang')
分析一个开源项目,往数据库里添加日志,为了避免写入日志信息影响正常业务,日志的插入方式采用了insert delayed的方式. 打印其数据库语句,复制到mysql执行报如下错误: ERROR 1616 (HY000): DELAYED option not supported for table 经过查找资料发现是有的mysql的存储引擎不支持此方式: INSERT DELAYED works only with MyISAM, MEMORY, ARCHIVE, and BLACKHOLE t
下面介绍Mysql和Sqlite和Sqlserver中,根据select的条件判断是否插入.例如: 一.Mysql中: INSERT INTO books (name) SELECT 'SongXingzhu' FROM dual WHERE NOT EXISTS (SELECT id FROM books WHERE id = 1) 二.Sqlite中: 由于Sqlite中没有临时表:dual 所以,需要这样写 INSERT INTO books (name) SELECT 'Songxin
在事务插入数据过程中,为防止其他事务向索引上该位置插入数据,会在插入之前先申请插入意向范围锁,而如果申请插入意向范围锁被阻塞,则事务处于gap before rec insert intention waiting的等待状态. MySQL官方文档解释如下: INSERT sets an exclusive lock on the inserted row. This lock is an index-record lock, not a next-key lock (that is, there
以下为MySQL 触发器insert 的3个示例演示(update类似) delimiter // create trigger InsertUser before insert on user for each row Begin insert into user_group(uid,gid) values(new.uid,'group4444444444'); end;// delimiter ; delimiter // create trigger InsertUser before i
先说说 insert 吧. 当EF执行insert时,如果我们传入的对象是有关联(1对多等)的话,它会执行多个语句 insert到多个表, 并且再select出来填充我们的属性(因为有些column默认值是sql设定的,比如id等,我们insert后要有最新的数据丫). using (EFDB db = new EFDB()) { db.prods.Add(new Prod { code = "mk100", name = "name", detail = new
从一个表复制数据插入到另外一个表,目标表中任何已存在的行都不会受影响. 语法: INSERT INTO table_xxx VALUES(); INSERT INTO table_xxx SELECT xxx from table_yyy; 当表A和表B的表结构一致时,直接插入即可. insert into A select * from B; 当表结构不一致时(字段大小.类型都相同) insert into A(col1, col2) select col1, col2 from B; END