参考下面示例看看

--构造数据
DROP TABLE IF EXISTS MROWUPDATE;
CREATE TABLE MROWUPDATE (
  ID INT NOT NULL,
  CNT VARCHAR(255)  NULL,
  PRIMARY KEY (ID)
);
 
INSERT INTO MROWUPDATE VALUES (1, 'SSS');
INSERT INTO MROWUPDATE VALUES (2, 'SZH');
INSERT INTO MROWUPDATE VALUES (3, '9999');
COMMIT;
---单条记录更新，改写merge into方式
MERGE INTO MROWUPDATE
AS
        T1 USING
        (
                SELECT 3 ID, 'SUPERMAN' CNT FROM DUAL
        )
AS
        T2 ON T1.ID=T2.ID
WHEN MATCHED THEN
        UPDATE SET T1.CNT=T2.CNT WHEN NOT MATCHED THEN
        INSERT VALUES
                (3, 'SUPERMAN'
                );
COMMIT;
----多条记录更新-DM中改写为MERGE INTO方式
MERGE INTO MROWUPDATE T1 USING
(
        SELECT 2 AS ID, 'UPDATE' AS CNT FROM DUAL
        
        UNION ALL
        
        SELECT '4', 'INSERT' FROM DUAL
)
T2 ON
(
        T1.ID = T2.ID
)
WHEN NOT MATCHED THEN
        INSERT
                (ID, CNT
                ) VALUES
                (T2.ID, T2.CNT
                ) WHEN MATCHED THEN
        UPDATE SET T1.CNT = T2.CNT;
COMMIT;

推荐一款专用于mysql迁移达梦的中间件：https://blog.csdn.net/xiaojia1001/article/details/132516102