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±í class

ID txtName
1 1
2 2
3 1
4 3
5 2
6 3

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ID txtname
1 1
2 2
4 3

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¾ÍÊÇ txtName Öظ´µÄʱºò£¬È¡×îСµÄIDºÅ

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select (select top 1 id from ±í where txtname=B.txtname) AS ID,
B.txtname from
(
select distinct txtname from ±í ) AS B

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select min(id),txtname from class group by txtname

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¾ÍÊÇ txtName Öظ´µÄʱºò£¬È¡×îСµÄIDºÅ

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select (select top 1 id from ±í where txtname=B.txtname) AS ID,
B.txtname from
(
select distinct txtname from ±í ) AS B

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Èç¹ûÈ¡×îСµÄºÅ£¬½«top 1 ¸Ä³É min(id)

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SQL code:

create table class
(
ID int null,
txtName varchar(20) null
)

insert into class (ID,txtName) values (1,'1')
insert into class (ID,txtName) values (2,'2')
insert into class (ID,txtName) values (3,'1')
insert into class (ID,txtName) values (4,'3')
insert into class (ID,txtName) values (5,'2')
insert into class (ID,txtName) values (6,'3')

select min(ID) ID,txtName from class group by txtName
drop table class


ID txtName
---------