日期:2014-05-18  浏览次数:20739 次

对一字段进行分组,且时间最大。sql怎么写?
测试SQL

SQL code

CREATE TABLE test.dbo.ST_WAS_R (
    ID varchar(50) NOT NULL,
    STCD char(8) NOT NULL,
    TM datetime NOT NULL,
    UPZ numeric(7,3) NOT NULL,
    DWZ numeric(7,3) NOT NULL,
    TGTQ numeric(9,3) NOT NULL,
    SWCHRCD char(1),
    SUPWPTN char(1),
    SDWWPTN char(1),
    MSQMT char(1),
    PRIMARY KEY (ID)
)
GO
INSERT INTO test.dbo.ST_WAS_R(ID, STCD, TM, UPZ, DWZ, TGTQ, SWCHRCD, SUPWPTN, SDWWPTN, MSQMT) VALUES ('1', 'TST00001', '2012-07-17 11:00:00.0', 2.000, 1.000, 1.000, null, null, null, null)
GO
INSERT INTO test.dbo.ST_WAS_R(ID, STCD, TM, UPZ, DWZ, TGTQ, SWCHRCD, SUPWPTN, SDWWPTN, MSQMT) VALUES ('2', 'TST00002', '2012-07-17 00:00:00.0', 1.000, 1.000, 1.000, null, null, null, null)
GO
INSERT INTO test.dbo.ST_WAS_R(ID, STCD, TM, UPZ, DWZ, TGTQ, SWCHRCD, SUPWPTN, SDWWPTN, MSQMT) VALUES ('3', 'TST00001', '2012-07-17 00:00:00.0', 1.000, 1.000, 1.000, null, null, null, null)
GO
INSERT INTO test.dbo.ST_WAS_R(ID, STCD, TM, UPZ, DWZ, TGTQ, SWCHRCD, SUPWPTN, SDWWPTN, MSQMT) VALUES ('4', 'TST00003', '2012-07-18 00:00:00.0', 2.000, 2.000, 2.000, null, null, null, null)
GO
INSERT INTO test.dbo.ST_WAS_R(ID, STCD, TM, UPZ, DWZ, TGTQ, SWCHRCD, SUPWPTN, SDWWPTN, MSQMT) VALUES ('5', 'TST00004', '2012-07-15 00:00:00.0', 3.000, 3.000, 3.000, null, null, null, null)
GO





结果需要 stcd,tm,upz

stcd进行分组,是唯一的,tm是时间最大的。非常 感谢 。、

------解决方案--------------------
select stcd,tm,upz
from ST_WAS_R
where id in (select id from ST_WAS_R a,(select stcd,max(tm) tm from ST_WAS_R group by stcd) b where a.stcd=b.stcd and a.tm=b.tm
)
------解决方案--------------------
SQL code
select a.stcd,a.tm,a.upz from ST_WAS_R a where exists (select 1 from (select MAX(tm)tm,stcd from ST_WAS_R group by stcd )aa where tm=a.tm and stcd=a.stcd)

------解决方案--------------------
SQL code
select a.stcd,a.tm,a.upz from ST_WAS_R a where exists (select 1 from (select MAX(tm)tm,stcd from ST_WAS_R group by stcd )aa where tm=a.tm and stcd=a.stcd)
/*
stcd    tm    upz
TST00001    2012-07-17 11:00:00.000    2.000
TST00002    2012-07-17 00:00:00.000    1.000
TST00003    2012-07-18 00:00:00.000    2.000
TST00004    2012-07-15 00:00:00.000    3.000
*/

------解决方案--------------------
SQL code
SELECT * FROM ST_WAS_R T
WHERE NOT EXISTS(SELECT 1 FROM ST_WAS_R WHERE stcd=T.stcd AND tm>T.tm)

------解决方案--------------------
SQL code
select
 * 
from
 st_was_r t
where
 tm=(select max(tm) from st_was_r where stcd=t.stcd)