Mysql檢查列是否存在並新增、修改、刪除列筆記

ALTER TABLE tbox_task ADD create_user varchar(50) DEFAULT NULL COMMENT '創建人' ;
ALTER TABLE tbox_task ADD create_time datetime DEFAULT CURRENT_TIMESTAMP COMMENT '創建時間';
ALTER TABLE tbox_task ADD modify_user varchar(50) DEFAULT NULL COMMENT '修改人' ;
ALTER TABLE tbox_task ADD modify_time datetime DEFAULT NULL ON UPDATE CURRENT_TIMESTAMP COMMENT '修改時間';



IF not exists( SELECT 1 FROM  information_schema.columns WHERE table_schema='taskm' AND table_name='tbox_task' AND column_name='create_user')
THEN
	ALTER TABLE tbox_task ADD create_user varchar(50) DEFAULT NULL COMMENT '創建人' ;
END IF 



DROP PROCEDURE IF EXISTS Pro_Temp_ColumnWork;
DELIMITER$$
-- 1表示新增列,2表示修改列類型,3表示刪除列
CREATE PROCEDURE Pro_Temp_ColumnWork(TableName VARCHAR(50),ColumnName VARCHAR(50),SqlStr VARCHAR(4000),CType INT)
BEGIN
DECLARE Rows1 INT;
SET Rows1=0;
SELECT COUNT(*) INTO Rows1  FROM INFORMATION_SCHEMA.Columns
WHERE table_schema= DATABASE() AND table_name=TableName AND column_name=ColumnName;
-- 新增列
IF (CType=1 AND Rows1<=0) THEN
SET SqlStr := CONCAT( 'ALTER TABLE ',TableName,' ADD COLUMN ',ColumnName,' ',SqlStr);
-- 修改列類型
ELSEIF (CType=2 AND Rows1>0)  THEN
SET SqlStr := CONCAT('ALTER TABLE ',TableName,' MODIFY  ',ColumnName,' ',SqlStr);
-- 刪除列
ELSEIF (CType=3 AND Rows1>0) THEN
SET SqlStr := CONCAT('ALTER TABLE  ',TableName,' DROP COLUMN  ',ColumnName);
ELSE  SET SqlStr :='';
END IF;
-- 執行命令
IF (SqlStr<>'') THEN 
SET @SQL1 = SqlStr;
PREPARE stmt1 FROM @SQL1;
EXECUTE stmt1;
END IF;
END$$
DELIMITER ;


-- 當前數據庫 TableName表名 ColumnName列名
-- 新增列
-- CALL Pro_Temp_ColumnWork ('表名','字段名','字段參數 ', 1);
-- CALL Pro_Temp_ColumnWork ('表名','字段名','int(11) NULL DEFAULT NULL AFTER `xxxxxxxxxxx`; ', 1);
CALL Pro_Temp_ColumnWork ('tbox_task','create_user','varchar(50) DEFAULT NULL COMMENT '創建人' ; ', 1);
CALL Pro_Temp_ColumnWork ('tbox_task','create_user','datetime DEFAULT NULL ON UPDATE CURRENT_TIMESTAMP COMMENT '修改時間';', 1);
-- 刪除列
-- CALL Pro_Temp_ColumnWork ('e_handcard_control','EntranceType','', 3);



-- 最後再執行一遍刪除存儲過程
DROP PROCEDURE IF EXISTS Pro_Temp_ColumnWork;







create procedure add_col_homework() BEGIN
IF EXISTS (SELECT column_name FROM information_schema.columns WHERE column_name = 'T_DT_HOMEWORK' AND column_name = 'RECOMMEND_RECORD')
THEN
   ALTER TABLE `T_DT_HOMEWORK`  DROP COLUMN `RECOMMEND_RECORD`;
END IF; 
   ALTER TABLE `T_DT_HOMEWORK` ADD COLUMN  `RECOMMEND_RECORD`  varchar(20) CHARACTER   SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL AFTER `RECOMMEND_ORG_CODE`;
END;
 
drop procedure if exists add_col_homework;

參考：

https://www.cnblogs.com/gilbert/p/10130009.html

https://blog.csdn.net/huangjin0507/article/details/49330413