表TB中，在gid為1和2中，要把souceid和type同時相同的找出來，只取一條 id souceid type gid 1?? s1 ????? t1?????? 1 2?? s1 ????? t1?????? 2 3?? s2 ????? t2?????? 1 4?? s2 ????? t2?????? 2 5?? s3?????? t3?????? 1 我了解的三種方法分別利用in、join、row_number 1.select * from TB where id in (select Max(id) from TB where gid in(1,2) group by souceid,type) 2.select * from TB A join (select Max(id) id from TB where gid in(1,2) group by souceid,type) B on A.id=B.id 3.select * from (select id,souceid,type,gid,row_number() over (partition by souceid,type order by id) as rn) A where A.rn=1 請高手指正，哪種方法最高效亦或是有更好的改進方法