Mysql判斷表字段或索引是否存在

判斷字段是否存在：

DROP PROCEDURE IF EXISTS schema_change; 
DELIMITER //
CREATE PROCEDURE schema_change() BEGIN 
DECLARE CurrentDatabase VARCHAR();
SELECT DATABASE() INTO CurrentDatabase;
IF NOT EXISTS (SELECT * FROM information_schema.columns WHERE table_schema=CurrentDatabase AND table_name = 'rtc_order' AND column_name = 'IfUpSend') THEN 
ALTER TABLE rtc_order
ADD COLUMN `IfUpSend` BIT NOT NULL DEFAULT COMMENT '是否上傳 是否上傳';
END IF; 
END// 
DELIMITER ; 
CALL schema_change(); 

判斷索引是否存在：

DROP PROCEDURE IF EXISTS schema_change; 
DELIMITER //
CREATE PROCEDURE schema_change() BEGIN 
DECLARE CurrentDatabase VARCHAR();
SELECT DATABASE() INTO CurrentDatabase;
IF NOT EXISTS (SELECT * FROM information_schema.statistics WHERE table_schema=CurrentDatabase AND table_name = 'rtc_phototype' AND index_name = 'index_name') THEN 
ALTER TABLE `rtc_Phototype` ADD INDEX index_name ( `imgtype` );
END IF; 
END// 
DELIMITER ; 
CALL schema_change(); 

從這兩段可以看出很多東西，具體可以自己試驗一下

關於小編給大家介紹的Mysql判斷表字段或索引是否存在的內容就給大家介紹到這裡，希望對大家有所幫助！