在SQL中查询此搜索的不同方法？

我在自学MS-SQL，并试图找到不同的方法，从这3个表中找出2012年按地区分组的已支付和未支付索赔的数量。如果有返回日期，则索赔未支付。如果返回日期为空，则索赔已支付

我会附上我运行过的代码，但我不确定是否有更好的方法

谢谢

代码如下：

SET dateformat ymd;

CREATE TABLE Claims
  (
     ClaimID      INT,
     SubID        INT,
     [Claim Date] DATETIME
  );

CREATE TABLE Phoneship
  (
     ClaimID           INT,
     [Shipping Number] INT,
     [Claim Date]      DATETIME,
     [Ship Date]       DATETIME,
     [Returned Date]   DATETIME
  );

CREATE TABLE Enrollment
  (
     SubID           INT,
     Enrollment_Date DATETIME,
     Channel         NVARCHAR(255),
     Region          NVARCHAR(255),
     Status          FLOAT,
     Drop_Date       DATETIME
  );

INSERT INTO [Phoneship]
            ([ClaimID],
             [Shipping Number],
             [Claim Date],
             [Ship Date],
             [Returned Date])
VALUES     (102,
            201,
            '2011-10-13 00:00:00',
            '2011-10-14 00:00:00',
            NULL);

INSERT INTO [Phoneship]
            ([ClaimID],
             [Shipping Number],
             [Claim Date],
             [Ship Date],
             [Returned Date])
VALUES     (103,
            202,
            '2011-11-02 00:00:00',
            '2011-11-03 00:00:00',
            '2011-11-20 00:00:00');

INSERT INTO [Phoneship]
            ([ClaimID],
             [Shipping Number],
             [Claim Date],
             [Ship Date],
             [Returned Date])
VALUES     (103,
            203,
            '2011-11-02 00:00:00',
            '2011-11-22 00:00:00',
            NULL);

INSERT INTO [Phoneship]
            ([ClaimID],
             [Shipping Number],
             [Claim Date],
             [Ship Date],
             [Returned Date])
VALUES     (105,
            204,
            '2012-01-16 00:00:00',
            '2012-01-17 00:00:00',
            NULL);

INSERT INTO [Phoneship]
            ([ClaimID],
             [Shipping Number],
             [Claim Date],
             [Ship Date],
             [Returned Date])
VALUES     (106,
            205,
            '2012-02-15 00:00:00',
            '2012-02-16 00:00:00',
            '2012-02-26 00:00:00');

INSERT INTO [Phoneship]
            ([ClaimID],
             [Shipping Number],
             [Claim Date],
             [Ship Date],
             [Returned Date])
VALUES     (106,
            206,
            '2012-02-15 00:00:00',
            '2012-02-27 00:00:00',
            '2012-03-06 00:00:00');

INSERT INTO [Phoneship]
            ([ClaimID],
             [Shipping Number],
             [Claim Date],
             [Ship Date],
             [Returned Date])
VALUES     (107,
            207,
            '2012-03-12 00:00:00',
            '2012-03-13 00:00:00',
            NULL);

INSERT INTO [Phoneship]
            ([ClaimID],
             [Shipping Number],
             [Claim Date],
             [Ship Date],
             [Returned Date])
VALUES     (108,
            208,
            '2012-05-11 00:00:00',
            '2012-05-12 00:00:00',
            NULL);

INSERT INTO [Phoneship]
            ([ClaimID],
             [Shipping Number],
             [Claim Date],
             [Ship Date],
             [Returned Date])
VALUES     (109,
            209,
            '2012-05-13 00:00:00',
            '2012-05-14 00:00:00',
            '2012-05-28 00:00:00');

INSERT INTO [Phoneship]
            ([ClaimID],
             [Shipping Number],
             [Claim Date],
             [Ship Date],
             [Returned Date])
VALUES     (109,
            210,
            '2012-05-13 00:00:00',
            '2012-05-30 00:00:00',
            NULL);

INSERT INTO [Claims]
            ([ClaimID],
             [SubID],
             [Claim Date])
VALUES     (101,
            12345678,
            '2011-03-06 00:00:00');

INSERT INTO [Claims]
            ([ClaimID],
             [SubID],
             [Claim Date])
VALUES     (102,
            12347190,
            '2011-10-13 00:00:00');

INSERT INTO [Claims]
            ([ClaimID],
             [SubID],
             [Claim Date])
VALUES     (103,
            12348723,
            '2011-11-02 00:00:00');

INSERT INTO [Claims]
            ([ClaimID],
             [SubID],
             [Claim Date])
VALUES     (104,
            12349745,
            '2011-11-09 00:00:00');

INSERT INTO [Claims]
            ([ClaimID],
             [SubID],
             [Claim Date])
VALUES     (105,
            12347190,
            '2012-01-16 00:00:00');

INSERT INTO [Claims]
            ([ClaimID],
             [SubID],
             [Claim Date])
VALUES     (106,
            12349234,
            '2012-02-15 00:00:00');

INSERT INTO [Claims]
            ([ClaimID],
             [SubID],
             [Claim Date])
VALUES     (107,
            12350767,
            '2012-03-12 00:00:00');

INSERT INTO [Claims]
            ([ClaimID],
             [SubID],
             [Claim Date])
VALUES     (108,
            12350256,
            '2012-05-11 00:00:00');

INSERT INTO [Claims]
            ([ClaimID],
             [SubID],
             [Claim Date])
VALUES     (109,
            12347701,
            '2012-05-13 00:00:00');

INSERT INTO [Claims]
            ([ClaimID],
             [SubID],
             [Claim Date])
VALUES     (110,
            12350256,
            '2012-05-15 00:00:00');

INSERT INTO [Claims]
            ([ClaimID],
             [SubID],
             [Claim Date])
VALUES     (111,
            12350767,
            '2012-06-30 00:00:00');

INSERT INTO [Enrollment]
            ([SubID],
             [Enrollment_Date],
             [Channel],
             [Region],
             [Status],
             [Drop_Date])
VALUES     (12345678,
            '2011-01-05 00:00:00',
            'Retail',
            'Southeast',
            1,
            NULL);

INSERT INTO [Enrollment]
            ([SubID],
             [Enrollment_Date],
             [Channel],
             [Region],
             [Status],
             [Drop_Date])
VALUES     (12346178,
            '2011-03-13 00:00:00',
            'Indirect Dealers',
            'West',
            1,
            NULL);

INSERT INTO [Enrollment]
            ([SubID],
             [Enrollment_Date],
             [Channel],
             [Region],
             [Status],
             [Drop_Date])
VALUES     (12346679,
            '2011-05-19 00:00:00',
            'Indirect Dealers',
            'Southeast',
            0,
            '2012-03-15 00:00:00');

INSERT INTO [Enrollment]
            ([SubID],
             [Enrollment_Date],
             [Channel],
             [Region],
             [Status],
             [Drop_Date])
VALUES     (12347190,
            '2011-07-25 00:00:00',
            'Retail',
            'Northeast',
            0,
            '2012-05-21 00:00:00');

INSERT INTO [Enrollment]
            ([SubID],
             [Enrollment_Date],
             [Channel],
             [Region],
             [Status],
             [Drop_Date])
VALUES     (12347701,
            '2011-08-14 00:00:00',
            'Indirect Dealers',
            'West',
            1,
            NULL);

INSERT INTO [Enrollment]
            ([SubID],
             [Enrollment_Date],
             [Channel],
             [Region],
             [Status],
             [Drop_Date])
VALUES     (12348212,
            '2011-09-30 00:00:00',
            'Retail',
            'West',
            1,
            NULL);

INSERT INTO [Enrollment]
            ([SubID],
             [Enrollment_Date],
             [Channel],
             [Region],
             [Status],
             [Drop_Date])
VALUES     (12348723,
            '2011-10-20 00:00:00',
            'Retail',
            'Southeast',
            1,
            NULL);

INSERT INTO [Enrollment]
            ([SubID],
             [Enrollment_Date],
             [Channel],
             [Region],
             [Status],
             [Drop_Date])
VALUES     (12349234,
            '2012-01-06 00:00:00',
            'Indirect Dealers',
            'West',
            0,
            '2012-02-14 00:00:00');

INSERT INTO [Enrollment]
            ([SubID],
             [Enrollment_Date],
             [Channel],
             [Region],
             [Status],
             [Drop_Date])
VALUES     (12349745,
            '2012-01-26 00:00:00',
            'Retail',
            'Northeast',
            0,
            '2012-04-15 00:00:00');

INSERT INTO [Enrollment]
            ([SubID],
             [Enrollment_Date],
             [Channel],
             [Region],
             [Status],
             [Drop_Date])
VALUES     (12350256,
            '2012-02-11 00:00:00',
            'Retail',
            'Southeast',
            1,
            NULL);

INSERT INTO [Enrollment]
            ([SubID],
             [Enrollment_Date],
             [Channel],
             [Region],
             [Status],
             [Drop_Date])
VALUES     (12350767,
            '2012-03-02 00:00:00',
            'Indirect Dealers',
            'West',
            1,
            NULL);

INSERT INTO [Enrollment]
            ([SubID],
             [Enrollment_Date],
             [Channel],
             [Region],
             [Status],
             [Drop_Date])
VALUES     (12351278,
            '2012-04-18 00:00:00',
            'Retail',
            'Midwest',
            1,
            NULL);

INSERT INTO [Enrollment]
            ([SubID],
             [Enrollment_Date],
             [Channel],
             [Region],
             [Status],
             [Drop_Date])
VALUES     (12351789,
            '2012-05-08 00:00:00',
            'Indirect Dealers',
            'West',
            0,
            '2012-07-04 00:00:00');

INSERT INTO [Enrollment]
            ([SubID],
             [Enrollment_Date],
             [Channel],
             [Region],
             [Status],
             [Drop_Date])
VALUES     (12352300,
            '2012-06-24 00:00:00',
            'Retail',
            'Midwest',
            1,
            NULL);

INSERT INTO [Enrollment]
            ([SubID],
             [Enrollment_Date],
             [Channel],
             [Region],
             [Status],
             [Drop_Date])
VALUES     (12352811,
            '2012-06-25 00:00:00',
            'Retail',
            'Southeast',
            1,
            NULL); 

和问题1

SELECT Count(ClaimID)                       AS 'Paid Claim',
       (SELECT Count(ClaimID)
        FROM   dbo.phoneship
        WHERE  [returned date] IS NOT NULL) AS 'Unpaid Claim'
FROM   dbo.Phoneship
WHERE  [Returned Date] IS NULL
GROUP  BY claimid 

问题2

SELECT Count(*)                             AS 'Paid Claims',
       (SELECT Count(*)
        FROM   dbo.Phoneship
        WHERE  [Returned Date] IS NOT NULL) AS 'Unpaid Claims'
FROM   dbo.Phoneship
WHERE  [Returned Date] IS NULL; 

问题3

Select Distinct(C.[Shipping Number]), Count(C.ClaimID) AS 'COUNT ClaimID', 
        A.Region, A.SubID 
From dbo.HSEnrollment A 
Inner Join dbo.Claims B On A.SubId = B.SubId 
Inner Join dbo.Phoneship C On B.ClaimID = C.ClaimID 
Where C.[Returned Date] IS NULL 
Group By A.Region, A.Subid, C.ClaimID, C.[Shipping Number] Order By A.Region

---

您需要将所有表连接在一起以获得区域。此版本假定每个索赔最多有一个on Phoneship记录：

SELECT e.region, count(*) as numclaims,
       sum(case when ps.ReturnedDate is not null then 1 else 0 end) AS 'Paid Claim',
       sum(case when ps.ReturnedDate is null then 1 else 0 end) AS 'Unpaid Claim'
FROM   claims c join
       enrollment e
       on c.sub_id = e.sub_id left outer join
       Phoneship ps
       on ps.claimid = c.claimdid
WHERE  [Returned Date] IS NULL
GROUP  BY e.region

如果有多个，那么计数将被关闭，因为每个电话将被计数，而不是每个索赔。要解决此问题，请将两个总和更改为：

count(distinct case when ps.ReturnedDate is not null then c.claimid end)
count(distinct case when ps.ReturnedDate is null then c.claimid end)

---

很难回答这个问题，因为我知道你在问什么，但还有很多其他小问题导致你的查询困难

我的答案
因此，要回答您问题的核心，我会做什么，如果且仅当我正确地解释了您的表结构（后面还有更多内容）

我没有包括索赔的数量，因为这会使数字偏离。我包含了两个查询，最终查询和细分查询。对于总和（因为您正在学习），我使用ROLLUP获得每个分组列的总和

SELECT 
    e.Region,
    paid = SUM(CASE WHEN p.[Returned Date] IS NULL THEN 1 ELSE 0 END),
    unpaid = SUM(CASE WHEN p.[Returned Date] IS NULL THEN 0 ELSE 1 END)
FROM claims c
    INNER JOIN enrollment e
        ON e.SubID = c.SubID
    INNER JOIN phoneship p
        ON p.ClaimID = c.ClaimID
GROUP BY e.Region
WITH ROLLUP

故障
这是使用内部虚拟表（结果表-结果集等）的子选择的细分查询。我这样做是为了证明一点

SELECT 
    x.Region,
    -- if the Returned Date is null then add 1, otherwise add 0
    paid = SUM(CASE WHEN x.ReturnedDate IS NULL THEN 1 ELSE 0 END),
    -- if the Returned Date is null then add 0, otherwise add 1
    unpaid = SUM(CASE WHEN x.ReturnedDate IS NULL THEN 0 ELSE 1 END)
FROM
(
-- Run this inner query to see what data you are actually working with
-- for your grouping/sums
SELECT 
    c.ClaimID,
    c.SubID,
    E = '#', -- This is just a separator
    e_SubID = e.SubID, -- This is equivalent to saying e.SubID AS e_SubID
    e.Region,
    P = '#', -- This is just a separator
    p_ClaimID = p.ClaimID,
    ShippingNo = p.[Shipping Number], -- Getting rid of those nasty spaces
    ReturnedDate = p.[Returned Date]
FROM claims c
    INNER JOIN enrollment e
        ON e.SubID = c.SubID
    -- Initially this was a LEFT JOIN but you are missing Claims in your 
    -- Phoneship table which will produce bogus results, therefore the
    -- INNER JOIN will filter out any rows that don't match
    INNER JOIN phoneship p
        ON p.ClaimID = c.ClaimID
) as x
GROUP BY x.Region
WITH ROLLUP

尽可能避免子选择，如果可以的话。它们的性能不是很好，但当然有时你无法避免

表结构/关系是执行此查询困难的根本原因。在查看了结构之后，我发现您正在复制数据（这是一个“否”），并且在将所有细节拉入一个漂亮的查询中时遇到了问题

我看到的问题领域（以及一些友好的建议）

您将ClaimDate列从Claims表复制到PhoneShip表。我不确定这些是否有不同的含义，但如果它是一个重复-避免这一点

可能应该删除索赔表中的SubID。最好将ClaimID作为（FK）放入注册表中

为Phoneship表提供自己的（PK）-这是为了便于使用，除了ClaimID和ShippingNumber的组合之外，使每一行都是唯一的。调查和调查

我有点怀疑使用NULL作为一个很好的指标是否有支付或未支付的东西。只有设计者才知道空字段意味着付费。为此，您最好使用一个默认值为零的位字段，并将其标记为NOTNULL，这样它就永远不会为NULL。在所有这些都将为您省去编写案例陈述的麻烦之后，您可以直接将位用于sum Ex:sum（x.Paid）。此外，由于各种原因，列有时可能被错误地标记为NULL

考虑将Channel和Region列完全从注册表中拉出。用整数PK将它们放在自己的表中。您可以使用ChannelID和RegionID在任何需要的地方引用PK。这样，如果名称需要更改，您就不必担心数据完整性问题（更新表集NameCol='a'，其中NameCol='b'--这可能会导致意外的重命名灾难）

将RegionID和ChannelID放入索赔表中。现在，如果遵循上面的步骤2（在注册表中有一个ClaimID FK），则注册表中不需要它

祝贺你主动学习这些东西。这是无价的知识（除非你上了大学，在这种情况下，它的价值大约是5万英镑或更糟……学生贷款……唉……。

试试这个

SELECT e.Region, COUNT(c.SubID) TotalClaims, COUNT(p.[returned date]) UnpaidClaims, COUNT(c.SubID)-COUNT(p.[returned date]) PaidClaims
FROM
    Claims c
    INNER JOIN enrollment e ON c.SubID = e.SubID
    INNER JOIN phoneship p ON p.ClaimID = c.ClaimID
GROUP BY e.Region

---

您已经包含了用于创建数据库的脚本，但没有包含用于获取所需值的脚本。您尝试的查询是什么？最好用它编辑您的问题，而不是将查询粘贴到评论中（我在前两次为您这样做了）。我知道这并不能回答您的问题，但我想马上告诉您避免在列名中使用空格。这可能会带来麻烦。有些人使用下划线，但我更喜欢驼峰式表示法——例如[Shipping Number]可以是ShippingNumber，在编写查询时更容易键入，您的开发人员（如果您有）也不会想杀了您：DSorry我不想再唠叨了，但只是另一个建议——不要使用DateTime，按照MS的建议使用DateTime2：即使在StackOverFlow@dyslexicanaboko上，为什么CamelCasers会大写第一个字母？他们不应该资本化吗？不是这样吗？