update A set oil_daily=(select oil_daily from B where A.well_id= B.WELL_ID AND A.PROD_DATE=B.PROD_DATE ) where well_id in(select well_id from B);
你是只想select 还是想update
update a set a.oil_daily = (select b.a.oil_daily where A.well_id= B.WELL_ID AND A.PROD_DATE=B.PROD_DATE) where a.oil_daily is null;
update A set oil_daily=(select oil_daily from B where A.well_id= B.WELL_ID AND A.PROD_DATE=B.PROD_DATE ) where well_id,PROD_DATE in(select well_id,PROD_DATE from B);
well_id prod_date oil_daily
1 2009-1-5
2 2009-1-6
3 2009-1-7表B
well_id prod_date oil_daily
1 2009-1-5 23
2 2009-1-6 25
3 2009-1-7 12
用B表的oil_daily去填充A表的oil_daily。(A表和B表的其余字段是不一样的)
well_id prod_date oil_daily
1 2009-1-5
2 2009-1-6
3 2009-1-7表B
well_id prod_date oil_daily
1 2009-1-5 23
2 2009-1-6 25
3 2009-1-7 12
用B表的oil_daily去填充A表的oil_daily。(A表和B表的其余字段是不一样的)