c语言获取系统日期函数（C# ling to sql 取多条记录最大时间）

var _setList = (from f in _postgreDbContext.settlements
                           group f by ( new { f.settlement_code })into g
                 select new
                 {
                   deal_time = g.Max(m => m.deal_time),
                   g.Key.settlement_code
                 }).AsNoTracking().ToList();

2012-05-31 C001 A店 136.00
2012-05-29 C001 A店 139.00
2012-05-29 C001 B店 5.00
2012-05-30 C001 B店 6.00

select * from tb t where not exists ( select 1 from tb where 编号 = t.编号 and 仓库 = t.仓库 and 日期 > t.日期)

create table cangku ( F_RQ datetime, F_BH VARCHAR(20), F_SL FLOAT )

INSERT INTO cangku VALUES('2012-05-31','C001',343) INSERT INTO cangku VALUES('2012-05-30','C001',34) INSERT INTO cangku VALUES('2012-05-30','C002',33) INSERT INTO cangku VALUES('2012-05-26','C002',23)

SELECT * FROM cangku T,(SELECT F_BH,MAX(F_RQ) rq FROM cangku GROUP BY F_BH) t2 where t.F_BH=t2.F_BH and t.F_RQ>=t2.rq 

select * from table a where a.date in (select max(b.date) from table b where b.id=a.id)