Mysql判断表字段或索引是否存在

判断字段是否存在：

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 '是否上传 是否上传';
END IF; 
END// 
DELIMITER ; 
CALL schema_change(); 

判断索引是否存在：

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(); 

从这两段可以看出很多东西，具体可以自己试验一下

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