《Mysql應(yīng)用Mysql判斷表字段或索引是否存在》要點(diǎn):
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MYSQL應(yīng)用判斷字段是否存在:
MYSQL應(yīng)用
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();
MYSQL應(yīng)用判斷索引是否存在:
MYSQL應(yīng)用
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();
MYSQL應(yīng)用從這兩段可以看出很多東西,具體可以自己試驗一下
MYSQL應(yīng)用關(guān)于小編給大家介紹的Mysql判斷表字段或索引是否存在的內(nèi)容就給大家介紹到這里,希望對大家有所贊助!
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