判断字段是否存在：
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DROP PROCEDURE IF EXISTS schema_change; DELIMITER //CREATE PROCEDURE schema_change() BEGINDECLARE 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') THENALTER TABLE rtc_orderADD 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：
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DROP PROCEDURE IF EXISTS schema_change; DELIMITER //CREATE PROCEDURE schema_change() BEGINDECLARE 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') THENALTER 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
关于小编给大家介绍的Mysql判断表字段或索引是否存在的内容就给大家介绍到这里，希望对大家有所帮助！
