本篇文章将通过存储过程来判断列(字段)是否存在。请看详情。

推荐课程：MySQL教程。

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();

mysql 判断字段否存在，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 `旧列名` `新列名` varchar(30) comment '字段说明';

end if;

end;

call proc_tempPro;

DROP PROCEDURE IF EXISTS proc_tempPro;

通过存储过程判断字段是否存在，不存在则增加：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;