多个连接子查询SQL Server 2008

Question

在左侧，您将看到我的设计为一个表，在右侧，您将在下面的SQL中看到子查询的结果。 我正在尝试在patientID,claimsFromDate,claimsThroughDate上的三个字段patientID,claimsFromDate,claimsThroughDate上加入子查询，并让外部查询将正确的tblClaims.ID与三部分连接相关联。

我得到的错误：

第3行，关键字附近不正确的语法选择and附近），第12行不正确的语法

select tblClaims.id, t.primaryCode
from t
(
select patientid, claimsfromdate, claimsthroughDate, primarycode from myTable
union
select patientid, claimsfromDate, claimsthroughDate, secondaryCode from myTable
union
select patientID, claimsfromdate, claimsthroughDate, tertiarycode from myTable

) as t
inner join t on tblclaims.patientid=t.patientid 
and tblclaims.claimsfromdate=t.claimsfromdate
and tblclaims.cllaimsthroughdate=t.claimsfromdate

编辑：内部查询是协调多列字段。 它返回150万行。 我运行的固定查询返回了350万，这是

select tblClaims.id, t.primarycode from ( select patientid, claimsfromdate, claimsthroughDate, primarycode from myTable ) as t inner join tblclaims on tblclaims.patientid=t.patientid and tblclaims.claimsfromdate=t.claimsfromdate and tblclaims.cllaimsthroughdate=t.claimsfromdate

Answer 1

尝试这个：

select tblClaims.id, t.primarycode 
from 
(
select patientid, claimsfromdate, claimsthroughDate, primarycode from myTable
) as t
inner join tblclaims on tblclaims.patientid=t.patientid 
and tblclaims.claimsfromdate=t.claimsfromdate
and tblclaims.cllaimsthroughdate=t.claimsfromdate

Answer 2

你尝试过使用Distinct吗？

select DISTINCT tblClaims.id, t.primarycode 
from 
(
    select patientid, claimsfromdate, claimsthroughDate, primarycode from myTable
) as t
inner join tblclaims on tblclaims.patientid=t.patientid 
and tblclaims.claimsfromdate=t.claimsfromdate
and tblclaims.cllaimsthroughdate=t.claimsfromdate