UPDATE SPXX
SET A.SP_ID = (select B.SP_ID
FROM B
WHERE A.SPCODE = B.SPCODE )
where exists(select B.SP_ID
FROM B
WHERE A.SPCODE = B.SPCODE ) ;
SET A.SP_ID = (select B.SP_ID
FROM B
WHERE A.SPCODE = B.SPCODE )
where exists(select B.SP_ID
FROM B
WHERE A.SPCODE = B.SPCODE ) ;
SET A.SP_ID = (select b.sp_id from spxx A,B where A.spcode=B.spcode)
仅当后面的 select语句返回单条时有作用。要不然就报错
set sp_id = (select b.sp_id from B b where a.spcode = b.spcode);
即可.