限制联合查询中的列

Question

我有一个联合查询，它从两个不同请求中检索信息，并将它们进行比较，并根据第三行中的比较显示YES，NO，NA。

下面是我的SQL查询

SELECT CAST(RR.reqestno AS VARCHAR(MAX)) reqestno, 
CAST(RR.receiveddate AS VARCHAR(MAX)) AS receiveddate, 
CAST(RR.rptcomments AS VARCHAR(MAX)) AS rptcomments, 
CAST(RR.reportfrequency AS VARCHAR(MAX)) AS reportfrequency, 
CAST(RR.schedule AS VARCHAR(MAX)) AS schedule, 
CAST(RR.schedulebasedon AS VARCHAR(MAX)) AS schedulebasedon, 
CAST(RR.clmsrvdtfrom AS VARCHAR(MAX)) AS clmsrvdtfrom, 
CAST(RR.clmsrvdtthru AS VARCHAR(MAX)) AS clmsrvdtthru, 
CAST(RR.clmpddtfrom AS VARCHAR(MAX)) AS clmpddtfrom, 
CAST(RR.clmpddtthru AS VARCHAR(MAX)) AS clmpddtthru, 
CAST(RR.customer AS VARCHAR(MAX)) AS customer 
from REPORT_REQUEST RR 
where RR.reqestno = xxxxxx 
UNION ALL 
SELECT CAST(RR.reqestno AS VARCHAR(MAX)) reqestno, 
CAST(RR.receiveddate AS VARCHAR(MAX)) AS receiveddate, 
CAST(RR.rptcomments AS VARCHAR(MAX)) AS rptcomments, 
CAST(RR.reportfrequency AS VARCHAR(MAX)) AS reportfrequency, 
CAST(RR.schedule AS VARCHAR(MAX)) AS schedule, 
CAST(RR.schedulebasedon AS VARCHAR(MAX)) AS schedulebasedon, 
CAST(RR.clmsrvdtfrom AS VARCHAR(MAX)) AS clmsrvdtfrom, 
CAST(RR.clmsrvdtthru AS VARCHAR(MAX)) AS clmsrvdtthru, 
CAST(RR.clmpddtfrom AS VARCHAR(MAX)) AS clmpddtfrom, 
CAST(RR.clmpddtthru AS VARCHAR(MAX)) AS clmpddtthru, 
CAST(RR.customer AS VARCHAR(MAX)) AS customer 
from REPORT_REQUEST RR 
where RR.reqestno = yyyyyy 
UNION ALL 
SELECT 
     CASE WHEN A.reqestno = B.reqestno THEN 'Yes' ELSE 'No' END as reqestno, 
     CASE WHEN A.receiveddate = B.receiveddate THEN 'Yes' ELSE 'No' END as receiveddate, 
     CASE WHEN A.rptcomments is null and B.rptcomments is null then 'NA' WHEN A.rptcomments = B.rptcomments THEN 'Yes' ELSE 'No' END rptcomments, 
     CASE WHEN A.reportfrequency = B.reportfrequency THEN 'Yes' ELSE 'No' END as reportfrequency, 
     CASE WHEN A.schedule = 'NONE' and B.schedule = 'NONE' THEN 'NA'WHEN A.schedule = B.schedule THEN 'Yes' ELSE 'No' END as schedule, 
     CASE WHEN A.schedulebasedon = 'NONE' and B.schedulebasedon = 'NONE' THEN 'NA' WHEN A.schedulebasedon = B.schedulebasedon THEN 'Yes' ELSE 'No' END as schedulebasedon, 
     CASE WHEN A.clmsrvdtfrom is null and B.clmsrvdtfrom is Null Then 'NA' WHEN A.clmsrvdtfrom = B.clmsrvdtfrom THEN 'Yes' ELSE 'No' END as clmsrvdtfrom, 
     CASE WHEN A.clmsrvdtthru is null and B.clmsrvdtthru is null then 'NA' WHEN A.clmsrvdtthru = B.clmsrvdtthru THEN 'Yes' ELSE 'No' END as clmsrvdtthru, 
     CASE WHEN A.clmpddtfrom is Null and B.clmpddtfrom is null then 'NA' WHEN A.clmpddtfrom = B.clmpddtfrom THEN 'Yes' ELSE 'No' END as clmpddtfrom, 
     CASE WHEN A.clmpddtthru is null and B.clmpddtthru is null then 'NA' WHEN A.clmpddtthru = B.clmpddtthru THEN 'Yes' ELSE 'No' END as clmpddtthru, 
     CASE WHEN A.customer = B.customer THEN 'Yes' ELSE 'No' END as customer 

FROM 
      (SELECT reqestno,receiveddate,rptcomments,reportfrequency,schedule,schedulebasedon,clmsrvdtfrom, 
clmsrvdtthru,clmpddtfrom,clmpddtthru,customer FROM REPORT_REQUEST WHERE reqestno = xxxxxx) AS A 
INNER JOIN 
       (SELECT reqestno,receiveddate,rptcomments,reportfrequency,schedule,schedulebasedon,clmsrvdtfrom, 
clmsrvdtthru,clmpddtfrom,clmpddtthru,customer FROM REPORT_REQUEST WHERE reqestno = yyyyyy) AS B 
     ON 1 = 1 

问题 我应该如何修改上面的查询，使之仅显示比较后有排在第三只“NO”的值列前两行并以某种方式隐藏其他列，比较返回YES或NA。我希望看到所有3行（2行数据+ 1行compariosn）

需要帮助请 感谢advan ce

Answer 1

基本上，您将UNION查询放入子查询并限制该查询。我不打算复制你的怪物查询 - 请SSCCE读了（Short, Self-Contained, Correct Example） - 但是：

SELECT r.* 
    FROM (SELECT Value1, Value2 
      FROM SomeWhere 
      WHERE SomeColumn = 234 
     UNION 
     SELECT Value1, Value2 
      FROM ElseWhere 
      WHERE ElseColumn = 432 
     ) AS r 
    WHERE Value1 > 37 OR Value2 < 91 

您可能还需要做OLAP代码的东西;你提到'第三行'是有问题的--SQL是一个基于集合的语言，排序并不自然（但可以完成）。

Answer 2

您可能希望将INNER JOIN的ON表达式更改为and连接的“否”条件。