mysql 判断表字段或索引是否存在，然后修改

判断字段是否存在：

 DROP PROCEDURE IF EXISTS schema_change;
 DELIMITER //
 CREATE PROCEDURE schema_change() BEGIN
 DECLARE  CurrentDatabase VARCHAR(100);
 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 0 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(100);
 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();