select
a.c1,
a.c2,
a.c3,
b.c2
from
tb a,
tb b
where
a.c3=b.c1
a.c1,
a.c2,
a.c3,
b.c2
from
tb a,
tb b
where
a.c3=b.c1
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go
create table tb([c1] varchar(10),[c2] varchar(10),[c3] varchar(10))
insert tb select 'a','aa','b'
union all select 'b','bb','c'
union all select 'c','cc','e'
union all select 'd','dd','a'
union all select 'e','ee','a'
goselect *,c4=(select c2 from tb where c1=t.c3) from tb t
/*
c1 c2 c3 c4
---------- ---------- ---------- ----------
a aa b bb
b bb c cc
c cc e ee
d dd a aa
e ee a aa(5 行受影响)
*/
if object_id('[tb]') is not null drop table [tb]
go
create table [tb]([c1] varchar(1),[c2] varchar(2),[c3] varchar(1))
insert [tb]
select 'a','aa','b' union all
select 'b','bb','c' union all
select 'c','cc','e' union all
select 'd','dd','a' union all
select 'e','ee','a'
---查询---
select
a.c1,
a.c2,
a.c3,
b.c2
from
tb a,
tb b
where
a.c3=b.c1---结果---
c1 c2 c3 c2
---- ---- ---- ----
a aa b bb
b bb c cc
c cc e ee
d dd a aa
e ee a aa(所影响的行数为 5 行)
go
create table tb([c1] varchar(10),[c2] varchar(10),[c3] varchar(10))
insert tb select 'a','aa','b'
union all select 'b','bb','c'
union all select 'c','cc','e'
union all select 'd','dd','a'
union all select 'e','ee','a'
go
select *,(select [c2] from tb where [c1]=t.c3) c4 from tb t
go
create table tb([c1] varchar(10),[c2] varchar(10),[c3] varchar(10))
insert tb select 'a','aa','b'
union all select 'b','bb','c'
union all select 'c','cc','e'
union all select 'd','dd','a'
union all select 'e','ee','a'
go
select *,(select [c2] from tb where [c1]=t.c3) c4 from tb t
c1 c2 c3 c4
---------- ---------- ---------- ----------
a aa b bb
b bb c cc
c cc e ee
d dd a aa
e ee a aa(5 行受影响)
go
create table tb([c1] varchar(10),[c2] varchar(10),[c3] varchar(10))
insert tb select 'a','aa','b'
union all select 'b','bb','c'
union all select 'c','cc','e'
union all select 'd','dd','a'
union all select 'e','ee','a'
go
select a.c1,a.c2,a.c3, b.c2 from tb a join tb b
on a.c3=b.c1c1 c2 c3 c4
---------- ---------- ---------- ----------
a aa b bb
b bb c cc
c cc e ee
d dd a aa
e ee a aa(5 行受影响)