我正在尝试将bacclaim表中的loss_dt从其他表bactrans更新为对Claim_id的其他表bactrans，其中loss_Dt> trans_dt

Question

I am setting loss_dt to trans_dt where loss_Dt >trans_Dt . loss_Dt is in bacclaim and trans_Dt is in bactrans both have claimid common

UPDATE bacclaim t1
   SET (t1.loss_dt) = (SELECT  t2.trans_dt
                         FROM bactrans t2
                        WHERE t1.claim > t2.claim)
 WHERE EXISTS (
    SELECT 1
      FROM bactrans t2
     WHERE t1.claim = t2.claim and t1.loss_dt>t2.trans_dt );

Answer 1

A MERGE statement might be what you are looking for:

MERGE INTO bacclaim dst
USING bactrans src
ON ( src.claimid = dst.claimid )
WHEN MATCHED THEN
  UPDATE SET loss_td = src.trans_dt
  WHERE src.loss_td > dst.trans_dt