自联接查询无效对象名称MSSQL 2008

Question

我正在尝试对此查询进行自我联接，并不断收到错误的invalid object name x

select row_number() over(order by patientid,admissiondate, claimsfromdate,datediff(dd,admissiondate, claimsfromdate)) as rn
    ,x.patientid, x.admissiondate, x.claimsfromdate, x.rehabwait

from
(
SELECT distinct 
        patientid
        ,admissiondate
        ,claimsfromdate
        ,DATEDIFF(dd, admissiondate, claimsfromdate) as rehabWait, hcpcs
FROM    Claims
WHERE   hcpcs in ('g0151', '97001', '97002', '9339') and claimsfromdate > admissiondate
) x inner join x as x2 on x.patientid=x2.patientid

如果不将其保存为视图或两次重写查询（一次是from，一次是内部联接），就无法做到这一点，可以吗？

Answer 1

使用CTE：

with x as (
     SELECT distinct patientid, admissiondate, claimsfromdate,
            DATEDIFF(dd, admissiondate, claimsfromdate) as rehabWait, hcpcs
     FROM    Claims
     WHERE   hcpcs in ('g0151', '97001', '97002', '9339') and
             claimsfromdate > admissiondate
    )
select row_number() over (order by patientid, admissiondate,
                                   claimsfromdate,
                                   datediff(dd,admissiondate, claimsfromdate)
                         ) as rn,
       x.patientid, x.admissiondate, x.claimsfromdate, x.rehabwait
from x inner join
     x as x2
     on x.patientid=x2.patientid

解决了原始问题后，我看不到您使用x2的目的。 它不会出现在“ SELECT”语句中。 您要做的就是为指定患者创建一个包含所有索赔的叉积。 也许这是合理的。 我希望group by成为此类查询的一部分。

Answer 2

您不能以这种方式JOIN表。 您可能需要创建一个引用两次的视图，或者可以执行以下操作：

SELECT row_number() over(order by patientid, admissiondate, claimsfromdate, rehabWait) as rn
    , x.patientid
    , x.admissiondate
    , x.claimsfromdate
    , x.rehabwait 
FROM 
(
    SELECT distinct 
            c1.patientid
            , c1.admissiondate
            , c1.claimsfromdate
            , DATEDIFF(dd, c1.admissiondate, c1.claimsfromdate) as rehabWait
            , c1.hcpcs
    FROM    Claims c1
    INNER JOIN Claims c2
        ON c1.patientid = c2.patientid
    WHERE  c1.hcpcs in ('g0151', '97001', '97002', '9339') and c1.claimsfromdate > c1.admissiondate
) x