例:表Table结构为日期字段T,INT字段N,文本S.需要查询N的每个不同数值中T最晚的元组.要求同时返回相关记录的S字段.
要求用一个SQL语句完成.在MS SQL Server中测试时, Select MAX(T) As MT, N From Table Group By N 可查得满足条件的记录的T,N字段,但是小生无论如何无法让它它结果中同时列出S字段.SOS~~~~~~~~~
要求用一个SQL语句完成.在MS SQL Server中测试时, Select MAX(T) As MT, N From Table Group By N 可查得满足条件的记录的T,N字段,但是小生无论如何无法让它它结果中同时列出S字段.SOS~~~~~~~~~
Select MAX(T) As MT, N,S From Table Group By N,S
有key用Group By 生成新表,和原来的表连。
From
(Select MAX(T) As MT, N From Table Group By N) as TT
inner join
(Select T, N, S From Table) SS
on TT.MT = SS.T and TT.N = SS.N
(Select Max(T) as t from t1 group by n)
XP的方法不行的,条件是是T,N同时相等才行.