本篇文章將通過存儲過程來判斷列(字段)是否存在。請看詳情。

推薦課程：MySQL教程。

判斷字段是否存在：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 '是否上傳 是否上傳';

END IF;

END//

DELIMITER ;

CALL schema_change();

mysql 判斷字段否存在，如果存在就修改字段：DROP PROCEDURE IF EXISTS proc_tempPro;

if(@count>0) THEN

alter table 表名 change column `舊列名` `新列名` varchar(30) comment '字段說明';

end if;

end;

call proc_tempPro;

DROP PROCEDURE IF EXISTS proc_tempPro;

通過存儲過程判斷字段是否存在，不存在則增加：DROP PROCEDURE IF EXISTS pro_AddColumn;

CREATE PROCEDURE pro_AddColumn() BEGIN

IF NOT EXISTS(SELECT 1 FROM information_schema.columns WHERE table_name='component' AND COLUMN_NAME='PRINT_CHECK_STATUS') THEN

ALTER TABLE component ADD PRINT_CHECK_STATUS int(10) default 0;

END IF;

IF NOT EXISTS(SELECT 1 FROM information_schema.columns WHERE table_name='component' AND COLUMN_NAME='PRINT_CHECK_TIME') THEN

ALTER TABLE component ADD PRINT_CHECK_TIME datetime NULL;

END IF;

IF NOT EXISTS(SELECT 1 FROM information_schema.columns WHERE table_schema=podcloud AND table_name='component' AND COLUMN_NAME='PRINT_CHECK_BACK_REASON') THEN

ALTER TABLE component ADD PRINT_CHECK_BACK_REASON varchar(500) default null;

END IF;

END;

CALL pro_AddColumn;

DROP PROCEDURE pro_AddColumn;

------------------------------------------------------------------------------------------------

DROP PROCEDURE IF EXISTS pro_AddIndex;

DELIMITER;

CREATE PROCEDURE pro_AddIndex() BEGIN 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 pro_AddIndex();

Drop procedure pro_AddIndex;

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