SQL Server，如何获取多个不同的项目

Question

我正在使用 SQL 服务器，

  id          3     | 4    | 5 | 6
  items       1 2 3 | 2 3 5| 6 | 1 2 5
    -------------------------
  # of items      3 | 4    | 5 | 5

所以，每个 id 都有项目（例如，3 有 3 个项目 - 1,2,3），对于每个项目，我想获得不同项目的数量。

所以， 3 有 3 个不同的项目 - 1, 2, 3
4 有 4 个不同的项目 - 1, 2, 3, 5
5 有 5 个不同的项目 - 1, 2, 3, 5, 6
6 有 5 个不同的项目 - 1, 2, 3, 5, 6

我可以通过运行 1 到 2、1 到 3、1 到 5 和 1 到 6 来执行计数（不同项目）但我想自动化这个过程并在一次运行中获得相同的结果。

这个想法是创建一个临时表并将一个项目放入其中，同时检查该项目是否已经在临时表中并为每个 id 打印不同项目的数量。

Answer 1

CREATE TABLE TEST
(
    id int, items int
)

INSERT INTO TEST
VALUES
(3, 1),
(3, 2),
(3, 3),
(4, 2),
(4, 3),
(4, 5),
(5, 6),
(6, 1),
(6, 2),
(6, 5)

SELECT B.id, COUNT(DISTINCT(A.ITEMS)) AS itemCount
FROM TEST A
INNER JOIN TEST B ON A.id <= B.id
GROUP BY B.ID

DROP TABLE TEST

Output: 
id  itemCount
3   3
4   4
5   5
6   5

Answer 2

假设您的数据采用以下格式：

Declare @table table
(
id int,
items varchar(10)
)

insert into @table values (3, '1 2 3');
insert into @table values (4, '2 3 5');
insert into @table values (5, '6');
insert into @table values (6, '1 2 5');

with cte as
(
Select id, b.Item
from @table a
cross apply [dbo].[Split] (items, ' ') b
)

Select y.id, count(distinct(x.Item)) AS [# of items]
from cte x
join cte y on x.id <= y.id
group by y.id

使用来自LINK的表值函数[dbo].[Split] 。

Answer 3

你可以如下：

DECLARE @Tbl TABLE (Id VARCHAR(10), Column3 VARCHAR(100), Column4 VARCHAR(100), Column5 VARCHAR(100), Column6 VARCHAR(100))
INSERT @Tbl
VALUES 
('items', '1 2 3', '2 3 5', '6', '1 2 5')   

;WITH CTE1
AS
(
    SELECT T.Id, T.Column3 AS ColumnId, CAST('<X>' + REPLACE(T.Column3,' ','</X><X>') + '</X>' as XML) AS FilterColumn FROM  @Tbl T UNION ALL
    SELECT T.Id, T.Column4 AS ColumnId, CAST('<X>' + REPLACE(T.Column4,' ','</X><X>') + '</X>' as XML) AS FilterColumn FROM  @Tbl T UNION ALL
    SELECT T.Id, T.Column5 AS ColumnId, CAST('<X>' + REPLACE(T.Column5,' ','</X><X>') + '</X>' as XML) AS FilterColumn FROM  @Tbl T UNION ALL
    SELECT T.Id, T.Column6 AS ColumnId, CAST('<X>' + REPLACE(T.Column6,' ','</X><X>') + '</X>' as XML) AS FilterColumn FROM  @Tbl T 
), CTE2
AS 
(
    SELECT 
        A.*,
        B.SplitData
    FROM
        CTE1 A CROSS APPLY
        (SELECT fdata.D.value('.','varchar(50)') AS SplitData FROM A.FilterColumn.nodes('X') as fdata(D)) B
)

SELECT
    T.Id ,
    (SELECT COUNT(DISTINCT C.SplitData) FROM CTE2 C WHERE C.Id = T.Id AND C.ColumnId IN (T.Column3)) Column3OfDistinct,
    (SELECT COUNT(DISTINCT C.SplitData) FROM CTE2 C WHERE C.Id = T.Id AND C.ColumnId IN (T.Column3, T.Column4)) Column4OfDistinct,
    (SELECT COUNT(DISTINCT C.SplitData) FROM CTE2 C WHERE C.Id = T.Id AND C.ColumnId IN (T.Column3, T.Column4, T.Column5)) Column5OfDistinct,
    (SELECT COUNT(DISTINCT C.SplitData) FROM CTE2 C WHERE C.Id = T.Id AND C.ColumnId IN (T.Column3, T.Column4, T.Column5, T.Column6)) Column6OfDistinct    
FROM
    @Tbl T

结果：

Id         Column3OfDistinct Column4OfDistinct Column5OfDistinct Column6OfDistinct
---------- ----------------- ----------------- ----------------- -----------------
items      3                 4                 5                 5

Answer 4

这应该可以帮助您：

    select
        id,
        count(items)
    from table_name
    group by id