Question

我有点想要获取我在sqlserver表中拥有的唯一客户的数量。存储数据的方式是：

+----------+----------+----------+
|  Value   |  Label   | ClientID |
+----------+----------+----------+
| Mr       | Title    |        1 |
| Sul      | Forename |        1 |
| Last     | Surname  |        1 |
| WD17 6JJ | Postcode |        1 |
+----------+----------+----------+

现在我必须根据姓，姓，邮政编码来计算\ list unique customer。有人可以帮忙吗

Answer 1

了解不同客户的数量

SELECT COUNT (DISTINCT ClientId)
FROM dbo.table

或使用pivot获取不同的列表

DECLARE @Table TABLE ( [Value] NVARCHAR(20), Label NVARCHAR(20), ClientID INT)
INSERT INTO @Table
([Value], Label, ClientID)
VALUES
(N'Mr', N'Title', 1),
(N'Sul', N'Forename', 1),
(N'Last', N'Surname', 1),
(N'WD17 6JJ', N'Postcode', 1) 


SELECT Pvt.Forename
     , Pvt.Surname
     , Pvt.Postcode
FROM @Table T
PIVOT ( MAX([Value]) FOR Label  IN ([Title], [Forename], [Surname], [Postcode])) AS Pvt
GROUP BY
     Pvt.Forename
    ,Pvt.Surname
    ,Pvt.Postcode

Answer 2

您可以这样做：

SELECT DISTINCT
       id.clientID, 
       title.title,
       Forename.Forename,
       Surname.Surname,
       Postcode.Postcode
FROM table id
CROSS APPLY (SELECT value AS title    FROM table  title WHERE label = 'title' AND title.clientID = id.clientID ) title
CROSS APPLY (SELECT value AS Forename FROM table  Forename WHERE label = 'Forename' AND Forename.clientID = id.clientID ) Forename
CROSS APPLY (SELECT value AS Surname  FROM table  Surname WHERE label = 'Surname' AND Surname.clientID = id.clientID ) Surname
CROSS APPLY (SELECT value AS Postcode FROM table  Postcode WHERE label = 'Postcode' AND Postcode.clientID = id.clientID ) Postcode

它不漂亮，但应该有用。

Answer 3

以下是两个可以提供所需结果的查询：

DECLARE @T table (Value varchar(255), Label varchar(255), ClientID int)

INSERT INTO @T
VALUES
('Mr', 'Title', 1)
, ('Sul', 'Forename', 1)
, ('Last', 'Surname', 1)
, ('WD17 6JJ', 'Postcode', 1)
, ('Dr', 'Title', 2) -- different Title will be ignored
, ('Sul', 'Forename', 2)
, ('Last', 'Surname', 2)
, ('WD17 6JJ', 'Postcode', 2)
, ('Mr', 'Title', 3)
, ('Sul2', 'Forename', 3) -- different Forename
, ('Last', 'Surname', 3)
, ('WD17 6JJ', 'Postcode', 3)

-- Using JOIN

SELECT DISTINCT
    T1.Value Forename
    , T2.Value Surname
    , T3.Value Postcode
FROM
    @T T1
    JOIN @T T2 ON T1.ClientID = T2.ClientID AND T2.Label = 'Surname'
    JOIN @T T3 ON T1.ClientID = T3.ClientID AND T3.Label = 'Postcode'
WHERE T1.Label = 'Forename'

-- Using PIVOT

SELECT DISTINCT
    Forename
    , Surname
    , Postcode
FROM 
    (
        SELECT
            Value
            , Label
            , ClientID
        FROM @T
    ) T
    PIVOT
    (
        MAX (Value)
        FOR Label IN
            (
                Forename, Surname, Postcode
            )
    ) P

用于获取转储数据的SQL

3 个答案: