1.如此執行語句不行，需要在 delimiter

  IF not EXISTS (
        SELECT
          *
        FROM
          information_schema. COLUMNS
        WHERE
          table_schema = ‘thc_rcm‘
          AND table_name = ‘Cs_AccountBillDetail‘
          AND column_name = ‘shopSetItemId‘
    ) THEN
    ALTER TABLE `thc_rcm`.`Cs_AccountBillDetail`
    
 
ADD COLUMN `shopSetItemId` varchar(64) DEFAULT NULL COMMENT ‘套餐的訂單明細ID‘ AFTER `itemId`;
 END IF;

2.這樣寫也不行，因為這樣的語句必須在存儲過程裏執行

DELIMITER //
  IF not EXISTS (
        SELECT
          *
        FROM
          information_schema. COLUMNS
        WHERE
          table_schema = ‘thc_rcm‘
          AND table_name = ‘Cs_AccountBillDetail‘
          AND column_name = ‘shopSetItemId‘
    ) THEN
    ALTER TABLE `thc_rcm`.`Cs_AccountBillDetail`
    ADD COLUMN `shopSetItemId` varchar(64) DEFAULT NULL COMMENT ‘套餐的訂單明細ID‘ AFTER `itemId`;
 END IF;
  END//
DELIMITER ;

3.OK

DELIMITER //
CREATE PROCEDURE thc_rcm_change ()
  BEGIN
  IF not EXISTS (
        SELECT
          *
        FROM
          information_schema. COLUMNS
        WHERE
          table_schema = ‘thc_rcm‘
          AND table_name = ‘Cs_AccountBillDetail‘
          AND column_name = ‘shopSetItemId‘
    ) THEN
    ALTER TABLE `thc_rcm`.`Cs_AccountBillDetail`
    ADD COLUMN `shopSetItemId` varchar(64) DEFAULT NULL COMMENT ‘套餐的訂單明細ID‘ AFTER `itemId`;
 END IF;
  END//
DELIMITER ;
CALL thc_rcm_change ();
DROP PROCEDURE
IF EXISTS thc_rcm_change;

4.將添加字段變為刪除字段則執行不通過，待解？？？？？？？？？？？

DELIMITER //
CREATE PROCEDURE thc_rcm_change ()
  BEGIN
  IF not EXISTS (
        SELECT
          *
        FROM
          information_schema. COLUMNS
        WHERE
          table_schema = ‘thc_rcm‘
          AND table_name = ‘Cs_AccountBillDetail‘
          AND column_name = ‘shopSetItemId‘
    ) THEN
    ALTER TABLE `thc_rcm`.`Cs_AccountBillDetail`
    drop COLUMN shopSetItemId;
 END IF;
  END//
DELIMITER ;
CALL thc_rcm_change ();
DROP PROCEDURE
IF EXISTS thc_rcm_change;

錯誤提示

Query execution failed

原因：
SQL 錯誤 [1064] [42000]: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ‘) THEN
ALTER TABLE `thc_rcm`.`Cs_AccountBillDetail` drop column setMealDetai‘ at line 1

Query execution failed

delimiter 與 存儲過程