Sql 案例问题，还是我'；我加入了我的行列

在Yellowfin中，我想返回一个值，我有3个表，叫做 成员资格， 会员计划， 成员资格UDP

成员是主成员，与其他两个成员有外部连接（链接可能存在，也可能不存在）

所以如果MemberPlans.PrevFundID有一个条目，我想要它， 否则，如果他们在3个月前加入，我希望成为会员UDPS.Property 否则我想要一个文本短语

目前，我每个memberships有两行。MemberNo，一行显示PRevFundID，另一行显示MembershipsUDPs，我只需要一行： 显示的sql是通过Yellowfin生成的

    SELECT DISTINCT
      "Memberships"."MemberNo",
      CASE
        WHEN PrevFundID IS NOT NULL  THEN PrevFundID
     ELSE 
       CASE
          WHEN JOINDATE >= DATEADD(mm, -3, GETDATE()) THEN Property 
          ELSE 'New to PHI'
       END
     END,
     "MembershipPlans"."PrevFundID",
     "MembershipUDPs"."Property"
   FROM "dbo"."Memberships"
   LEFT OUTER JOIN "dbo"."MembershipPlans"
     ON ("Memberships"."MemberNo" = "MembershipPlans"."MemberNo")
   LEFT OUTER JOIN "dbo"."MembershipUDPs"
     ON ("Memberships"."MemberNo" = "MembershipUDPs"."MemberNo")
    AND ("MembershipUDPs"."PropertyID" = N'TF')
   WHERE ("Memberships"."IsProspect" = N'N')
     AND ("Memberships"."JoinDate" BETWEEN '20140701 00:00:00.0' AND
                                           '20150630 23:59:59.997'
          AND ("Memberships"."PaidToDate" >= "Memberships"."JoinDate"
           OR "Memberships"."TermDate" IS NULL)
         )

---

在收到关于完整代码的注释后，我编辑了这篇文章。

左侧外部连接链导致了这里的问题。您需要MembershipPlans表或MembershipUDPS表中的任一行，但不能同时使用这两个行。SQL中也有一些无关的条件；你不需要两个case语句，paren可能会绊倒你（事实上，他们可能会绊倒我，这段代码有点难读）

试试这个：

SELECT DISTINCT
   "Memberships"."MemberNo",
    CASE
      WHEN PrevFundID IS NOT NULL  THEN PrevFundID
      WHEN JOINDATE >= DATEADD(mm, -3, GETDATE()) THEN Property 
      ELSE 'New to PHI' 
    END,
   "MembershipPlans"."PrevFundID",
   NULL
FROM "dbo"."Memberships"
INNER JOIN "dbo"."MembershipPlans"
ON "Memberships"."MemberNo" = "MembershipPlans"."MemberNo"
WHERE "Memberships"."IsProspect" = N'N'
AND "Memberships"."JoinDate" BETWEEN '20140701 00:00:00.0' AND '20150630 23:59:59.997'
AND ("Memberships"."PaidToDate" >= "Memberships"."JoinDate"
      OR "Memberships"."TermDate" IS NULL)
UNION ALL
SELECT DISTINCT
   "Memberships"."MemberNo",
    CASE
      WHEN PrevFundID IS NOT NULL  THEN PrevFundID
      WHEN JOINDATE >= DATEADD(mm, -3, GETDATE()) THEN Property 
      ELSE 'New to PHI' 
    END,
   NULL,
   "MembershipUDPs"."Property",
FROM "dbo"."Memberships"
INNER JOIN "dbo"."MembershipUDPs"
ON "Memberships"."MemberNo" = "MembershipUDPs"."MemberNo"
WHERE "Memberships"."IsProspect" = N'N'
AND "Memberships"."JoinDate" BETWEEN '20140701 00:00:00.0' AND '20150630 23:59:59.997'
AND ("Memberships"."PaidToDate" >= "Memberships"."JoinDate"
      OR "Memberships"."TermDate" IS NULL)

---

如果您想要相同的列，那么在投影列表中去掉空值（查询顶部的

选择…NULL

。

嗨，我最终解决了这个问题。我之所以使用外部联接，是因为表之间的关系不是一对多就是一对多，但我使用子查询重写了查询。SQL的格式是通过Yellowin创建的：

SELECT 
   T0.C0,
   T1.C0,
   T2.C0,
   CASE
      WHEN T1.C0 IS NULL
      AND T2.C0 IS NULL THEN 1
   END,
   CASE
      WHEN T2.C0 = 'NM' THEN 'New to PHI'
      WHEN T1.C0 IS NOT NULL
      OR T2.C0 IS NOT NULL THEN 'Transferred'
      ELSE 'New to PHI'
   END,
   T0.C1
FROM (
   SELECT DISTINCT
      "Memberships"."MemberNo" AS C0,
      COUNT("Memberships"."MemberNo") AS C1
   FROM "dbo"."Memberships"
   WHERE (
      "Memberships"."IsProspect" = N'N'
   )
   AND (
      (
         "Memberships"."PaidToDate" > "Memberships"."JoinDate"
         OR "Memberships"."HealthTermEntryDate" IS NULL
      )
      AND "Memberships"."JoinDate" BETWEEN '20150701 00:00:00.0' AND '20160630 23:59:59.997'
   )
   GROUP BY 
      "Memberships"."MemberNo"

) T0
LEFT OUTER JOIN (
   SELECT DISTINCT
      "MembershipPlans"."PrevFundID" AS C0,
      "Memberships"."MemberNo" AS C1
   FROM "dbo"."Memberships"
   INNER JOIN "dbo"."MembershipPlans"
   ON (
      "Memberships"."MemberNo" = "MembershipPlans"."MemberNo"
   )
   WHERE (
      "Memberships"."IsProspect" = N'N'
   )
   AND (
      "MembershipPlans"."IsPrevCover" IN (N'Y')
   )

) T1
ON T0.C0 = T1.C1
LEFT OUTER JOIN (
   SELECT DISTINCT
      "MembershipUDPs"."Property" AS C0,
      "MembershipUDPs"."MemberNo" AS C1
   FROM "dbo"."Memberships"
   LEFT OUTER JOIN "dbo"."MembershipUDPs"
   ON (
      "Memberships"."MemberNo" = "MembershipUDPs"."MemberNo"
   )
   WHERE (
      "Memberships"."IsProspect" = N'N'
   )
   AND (
      "MembershipUDPs"."PropertyID" IN (N'TF   ')
      AND "Memberships"."JoinDate" >= '20150608 00:00:00.0'
   )

) T2
ON T0.C0 = T2.C1

---

除非您显示完整的查询，否则很难回答。该case表达式只能返回一个值，因此如果您得到多行，那么其他原因就是原因。请显示整个查询。现在显示完整代码。

成员资格计划

或

成员资格UDP

中必须有多个匹配行（或者在这种情况下，您将获得四条记录）。例如，如果

成员资格计划

中有多行，您希望使用哪一条记录？我想这是最近的一次？@Chris会员可以有多个会员计划或UDP吗？据我所知，这将是您获取多行的唯一原因。