Mysql变量
用户变量 [@...]
CREATE TEMPORARY TABLE IF NOT EXISTS t2
(
PNo INT NOT NULL,
PName VARCHAR(50) NOT NULL
);
INSERT INTO t2 VALUES(1,'A'),(2,'B'),(3,'C'),(4,'D');
SELECT COUNT(1) INTO @count FROM t2;
SELECT @count;
SET @p1='set @p1';
SELECT @p1;
Declare方式定义变量 该定义方式只能用于函数与存储里面
方式1:Declare 变量名 类型
方式2:Declare 变量名 类型 DEFAULT 默认值
没有DEFAULT 默认为NULL
DROP PROCEDURE IF EXISTS mytest;
CREATE PROCEDURE mytest(ax VARCHAR(20))
BEGIN
DECLARE pcname VARCHAR(255) DEFAULT '';
DECLARE pcount INT DEFAULT 0;
DROP TEMPORARY TABLE IF EXISTS t2;
CREATE TEMPORARY TABLE IF NOT EXISTS t2
(
PNo INT NOT NULL,
PName VARCHAR(50) NOT NULL
);
INSERT INTO t2 VALUES(1,'A'),(2,'B'),(3,'C'),(4,'D');
SELECT pcname;
SET pcname='ABC';SELECT pcname;
SELECT COUNT(1) INTO pcount FROM t2;
SELECT pcount;
END