MySql基础整理

大家好，又见面了，我是全栈君

use abccs; select * from mytable2 limit 3,4; call sp_name1(1,@nn); select @nn; select length(‘sdaf’);

select sum(1) from mytable2 where mytable2.name=’8′; select sum_hell(‘abv’); select * from t; #描述表t结构 desc t; #添加一列设置为主键 alter table t add id int,add primary key (id); #删除列my_order alter table t drop column my_order;– alter table t add my_order char(1) default ‘Y’; #修改表列类型 alter table t modify my_order varchar(10); alter table t change my_order my_order char(1); #修改表 列名address1 为id alter table t change column address1 id int; #删除存储过程testName drop procedure testName; delimiter // create procedure testName(in name varchar(10),out para varchar(10)) begin declare deName varchar(10); #NOT FOUND,SQLEXCEPTION,SQLWARNING declare continue handler for not found,sqlexception,sqlwarning set @sp2=10;#begin end; set @sp1=1; delete from t where id <10; set @sp1=2; insert into t values(2,3); set @sp1=3; insert into t values(2,3); set @sp1=4; select id into para from t; end; call testName(2,@a); select @a, @sp1, @sp2; // delimiter // create procedure testTration() begin declare continue handler for not found,sqlexception,sqlwarning rollback; start transaction; insert into t values(3,’Y’); insert into t values(4,’Y’); commit; end; call testTration();

#用户变量 set @cvar=23; ##系统变量 #全局系统变量 set global eee=234 #会话系统变量 set @@var # 单行注释 — 单行注释 /* 多行注释 eeee */

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