sql - 多连接子查询 SQL Server 2008

Question

在左边你会看到我为一个表设计的，在右边你会看到下面 SQL 中子查询的结果。我正在尝试patientID,claimsFromDate,claimsThroughDate在 tblClaims 的三个字段上加入子查询，并让外部查询将正确tblClaims.ID的与三部分连接相关联。

我得到的错误：

第 3 行，关键字附近的and语法不正确 选择 ) 附近的语法不正确，第 12 行

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 350 万，即

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

你试过用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