Mysql 如何在CREATEDATABASE语句中使用变量
我有以下程序:Mysql 如何在CREATEDATABASE语句中使用变量,mysql,Mysql,我有以下程序: DELIMITER // create DEFINER = 'root'@'localhost' procedure create_db(name TEXT) BEGIN DECLARE temp TEXT; DECLARE user TEXT; SELECT SCHEMA_NAME FROM INFORMATION_SCHEMA.SCHEMATA WHERE SCHEMA_NAME = name INTO temp; if temp = name then
DELIMITER //
create DEFINER = 'root'@'localhost' procedure create_db(name TEXT)
BEGIN
DECLARE temp TEXT;
DECLARE user TEXT;
SELECT SCHEMA_NAME FROM INFORMATION_SCHEMA.SCHEMATA WHERE SCHEMA_NAME = name INTO temp;
if temp = name then
SIGNAL SQLSTATE '45002' SET MESSAGE_TEXT = 'This database already exist';
else
SELECT USER() INTO user;
create database name;
grant all privileges on name.* to user with grant option;
END IF;
END //
DELIMITER ;
它工作得很好,只是它提供了字面上的“name”而不是变量名的值。我如何告诉它名称是一个变量?类似于php中的$name之类的东西。我浏览了许多文档,但它们都使用了无前缀的变量。您只需要使用准备好的语句,以下是工作代码:
DELIMITER //
drop procedure if exists create_db //
create procedure create_db(name TEXT)
BEGIN
DECLARE temp TEXT;
DECLARE user TEXT;
SELECT SCHEMA_NAME FROM INFORMATION_SCHEMA.SCHEMATA WHERE SCHEMA_NAME = name INTO temp;
if temp = name then
SIGNAL SQLSTATE '45002' SET MESSAGE_TEXT = 'This database already exist';
else
SELECT USER() INTO user;
SET @s = CONCAT('CREATE DATABASE ', name);
PREPARE stmt_create FROM @s;
EXECUTE stmt_create;
DEALLOCATE PREPARE stmt_create;
SET @s = CONCAT('GRANT ALL PRIVILEGES ON ', name, '.* TO ', user, ' WITH GRANT OPTION');
PREPARE stmt_grant FROM @s;
EXECUTE stmt_grant;
DEALLOCATE PREPARE stmt_grant;
END IF;
END //
DELIMITER ;