查找当年未续订的会员答案

【问题标题】：finding members who have not renewed for current year查找当年未续订的会员
【发布时间】：2014-02-18 03:48:53
【问题描述】：

Membership 表包含每个成员每年 1 条记录（在此示例中进行了简化。

我想要尚未续订 2014 年的 2013 年成员。这与我逻辑上的结果一样接近，但我得到空结果

SELECT  Users.UserID
      , YEAR(Membership.MemYear) AS MemYear
      , Users.MailTo
      , Users.StreetAddress
      , Users.Address2
      , Users.City
      , StateLookup.State
      , Users.Zip
FROM Users INNER JOIN Membership 
ON Users.UserID = Membership.UserID 
INNER JOIN StateLookup 
ON Users.StateID = StateLookup.StateID 
where YEAR(Membership.MemYear) = '2013' 
and not exists 
(SELECT  Users.UserID, YEAR(Membership.MemYear) AS MemYear
       , Users.MailTo, Users.StreetAddress, Users.Address2
       , Users.City, StateLookup.State, Users.Zip
FROM Users INNER JOIN Membership AS Membership_1 
ON Users.UserID = Membership_1.UserID 
INNER JOIN StateLookup 
ON Users.StateID = StateLookup.StateID 
where YEAR(Membership_1.MemYear)='2014')

帮助表示赞赏！

【问题讨论】：

为什么需要状态查找，'UserID' 不是唯一的吗？
Member 表中 MemYear 列的数据类型是什么？？

标签： sql sql-server

【解决方案1】：

您可以使用 MAX(MemYear) 来查找拥有 2013 年最大 MemYear 的人。这意味着他们在 2013 年处于活跃状态并且没有续订。

SELECT Users.UserID
      , Users.MailTo
      , Users.StreetAddress
      , Users.Address2
      , Users.City
      , StateLookup.State
      , Users.Zip
FROM Users 
INNER JOIN Membership 
    ON Users.UserID = Membership.UserID 
INNER JOIN StateLookup 
    ON Users.StateID = StateLookup.StateID 
GROUP BY Users.UserID
      , Users.MailTo
      , Users.StreetAddress
      , Users.Address2
      , Users.City
      , StateLookup.State
      , Users.Zip
HAVING MAX(YEAR(Membership.MemYear)) = 2013

【讨论】：

【解决方案2】：

我认为如果“用户 ID”是唯一的，您可以这样做。

SELECT Users.UserID  
  , YEAR(Membership.MemYear) AS MemYear  
  , Users.MailTo  
  , Users.StreetAddress  
  , Users.Address2  
  , Users.City  
  , StateLookup.State 
  , Users.Zip  
 FROM Users INNER JOIN Membership   
 ON Users.UserID = Membership.UserID   
 INNER JOIN StateLookup   
 ON Users.StateID = StateLookup.StateID   
 WHERE Membership.MemYear = '2013'   
 AND Users.UserID NOT IN  
   (SELECT UserID FROM Membership WHERE MemYear = '2014');

【讨论】：

【解决方案3】：

尝试如下更改查询的底部：

您忘记引用查询的另一层。假设您的查询的其余部分没问题，这应该可以解决该问题。

SELECT Users.UserID,
       YEAR(Membership.MemYear) AS MemYear,
       Users.MailTo,
       Users.StreetAddress,
       Users.Address2,
       Users.City,
       StateLookup.State,
       Users.Zip
  FROM Users
 INNER JOIN Membership
    ON Users.UserID = Membership.UserID
 INNER JOIN StateLookup
    ON Users.StateID = StateLookup.StateID
 where YEAR(Membership.MemYear) = '2013'
   and not exists (SELECT x.UserID,
               YEAR(Membership.MemYear) AS MemYear,
               x.MailTo,
               x.StreetAddress,
               x.Address2,
               x.City,
               StateLookup.State,
               x.Zip
          FROM Users x
         INNER JOIN Membership AS Membership_1
            ON x.UserID = Membership_1.UserID
         INNER JOIN StateLookup
            ON x.StateID = StateLookup.StateID
         where YEAR(Membership_1.MemYear) = '2014'
           and x.UserID = Users.UserID)

【讨论】：

作为参考，您在存在子查询的选择列表中选择什么并不重要，您可能一直认为您使用的是 IN 子查询。解决该查询的另一种方法是将“不存在”更改为“不在”。

【解决方案4】：

SELECT  Users.UserID
      , MemYear 
      , Users.MailTo
      , Users.StreetAddress
      , Users.Address2
      , Users.City
      , StateLookup.State
      , Users.Zip
FROM Users INNER JOIN Membership 
ON Users.UserID = Membership.UserID 
INNER JOIN StateLookup 
ON Users.StateID = StateLookup.StateID 
where Users.UserID  NOT IN 
                      (SELECT UserID
                       FROM Membership
                       where MemYear ='2014')

【讨论】：

【解决方案5】：

SELECT  Users.UserID
  , YEAR(Membership.MemYear) AS MemYear
  , Users.MailTo
  , Users.StreetAddress
  , Users.Address2
  , Users.City
  , StateLookup.State
  , Users.Zip
FROM Users INNER JOIN Membership ON Users.UserID = Membership.UserID 
INNER JOIN StateLookup ON Users.StateID = StateLookup.StateID 
where YEAR(Membership.MemYear) <= 2013   /* If it Integer you don't need '' */

为什么要使用子查询？

【讨论】：

我添加了少于 2013 年或等于 2013 年的数字，而且它不包括 2014 年，简单点。
Membership 每年每个用户都有一条记录...这意味着您的查询可以返回 2014 年的人的结果。尽管您不一定需要第二个选择语句。我改为显示HAVING。
@MikeSmithDev 我的赌注，没有查看重复名称的成员表，没错，有子句可以解决问题