select * from tb a where not exists(select 1 from tb where id=a.id and inputtime<a.inputtime)
select * from tb a where inputtime=(select min(inputtime) from tb where id=a.id)
CREATE TABLE test ( 客户 VARCHAR(20) , 下单日期 DATETIME ) INSERT INTO test VALUES ( '客户1', '2011-01-01' ) INSERT INTO test VALUES ( '客户1', '2011-04-01' )INSERT INTO test VALUES ( '客户2', '2011-01-02' ) INSERT INTO test VALUES ( '客户2', '2011-04-03' )SELECT * FROM test SELECT 客户 , MIN(下单日期) FROM test GROUP BY 客户
where not exists(select 1 from tb where id=a.id and inputtime<a.inputtime)
where inputtime=(select min(inputtime) from tb where id=a.id)
CREATE TABLE test
(
客户 VARCHAR(20) ,
下单日期 DATETIME
)
INSERT INTO test
VALUES ( '客户1', '2011-01-01' )
INSERT INTO test
VALUES ( '客户1', '2011-04-01' )INSERT INTO test
VALUES ( '客户2', '2011-01-02' )
INSERT INTO test
VALUES ( '客户2', '2011-04-03' )SELECT *
FROM test
SELECT 客户 ,
MIN(下单日期)
FROM test
GROUP BY 客户