[英]Count Distinct over partition by sql
I have a table like 我有一张桌子
col1ID col2String Col3ID Col4String Col5Data
1 xxx 20 abc 14-09-2018
1 xxx 20 xyz 14-09-2018
2 xxx 30 abc 14-09-2018
2 xxx 30 abc 14-09-2018
I would like to add column which count how many different strings I have in col4String group by col1ID and col3ID. 我想添加一列,该列通过col1ID和col3ID计算col4String组中有多少个不同的字符串。
So something like 所以像
COUNT(DISTINCT (Col4String)) over (partition by col1ID, col3ID)
but it doesn't work, I receive an error 但它不起作用,我收到一个错误
Use of DISTINCT is not allowed with the OVER clause.
OVER子句不允许使用DISTINCT。
Msg 102, Level 15, State 1, Line 23.消息102,第15级,州1,第23行。
I have more columns like col2String, col5Data but they shouldn´t be affected, so I can't use distinct at the beginning of SELECT
, and dense_rank()
also doen´t seems to work in my case. 我有更多列,例如col2String和col5Data,但它们不应该受到影响,因此我不能在
SELECT
的开头使用distinct,而且我的情况下dense_rank()
似乎也不起作用。
Thank You for help. 谢谢你的帮助。
Try this: 尝试这个:
DECLARE @DataSource TABLE
(
[col1ID] INT
,[col2String] VARCHAR(12)
,[Col3ID] INT
,[Col4String] VARCHAR(12)
,[Col5Data] DATE
);
INSERT INTO @DataSource
VALUES (1, 'xxx', 20, 'abc', '2018-09-14')
,(1, 'xxx', 20, 'xyz', '2018-09-14')
,(2, 'xxx', 30, 'abc', '2018-09-14')
,(2, 'xxx', 30, 'abc', '2018-09-14');
SELECT *
,dense_rank() over (partition by col1ID, col3ID order by [Col4String]) + dense_rank() over (partition by col1ID, col3ID order by [Col4String] desc) - 1
FROM @DataSource
Obviously distinct is not supported in window function in SQL Server, therefore, you may use a subquery instead. 显然,SQL Server的窗口功能不支持distinct,因此,您可以改用子查询。 Something along these lines:
遵循以下原则:
select (
select COUNT(DISTINCT Col4String)
from your_table t2
where t1.col1ID = t2.col1ID and t1.col3ID = t2.col3ID
)
from your_table t1
Try this way; 尝试这种方式;
select * from TableX X
outer apply(select count(*) as stringCount , X2.Col4String
from TableX X2 on X.col1ID= X2.col1ID and X.col3ID = X2.col3ID
group by X2.Col4String ) K
I would use APPLY
: 我会使用
APPLY
:
SELECT t.*, t1.Col4String_Cnt
FROM table t CROSS APPLY
(SELECT COUNT(DISTINCT t1.Col4String) AS Col4String_Cnt
FROM table t1
WHERE t1.col1ID = t.col1ID AND t1.col3ID = t.col3ID
) t1;
You can do this with an additional level of window functions. 您可以使用附加级别的窗口功能来执行此操作。 One method uses
dense_rank()
: 一种方法使用
dense_rank()
:
SELECT . . .,
MAX(DR) OVER (PARTITION BY col1ID, col3ID)
FROM (SELECT t.*,
DENSE_RANK() OVER (PARTITION BY col1ID, col3ID ORDER BY Col4String) as dr
FROM t
) t
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