Question

我有一般的查询，例如：

SELECT col1, col2, col3, col4
FROM Table1 AS t1
GROUP BY col1, col2, col3, col4

它将返回类似于：

的表格

col1   col2   col3   col4    
data1  data2  data3  data4
data1  data2  data3  data5
data10 data11 data12 data13
data10 data11 data12 data14
data10 data11 data12 data15

我需要获取col1的计数才能显示data1两次返回，data10返回三次。该表应如下所示：

col1   col2   col3   col4   Count  
data1  data2  data3  data4  2
data1  data2  data3  data5  2
data10 data11 data12 data13 3
data10 data11 data12 data14 3
data10 data11 data12 data15 3

我在select语句中尝试了count（*），但这不起作用。

Answer 1

您可以使用OVER子句（SQL Server 2008 +）：

SELECT col1, col2, col3, col4, COUNT(*) OVER(PARTITION BY col1) [Count]
FROM Table1 AS t1

结果是：

╔════════╦════════╦════════╦════════╦═══════╗
║  COL1  ║  COL2  ║  COL3  ║  COL4  ║ COUNT ║
╠════════╬════════╬════════╬════════╬═══════╣
║ data1  ║ data2  ║ data3  ║ data4  ║     2 ║
║ data1  ║ data2  ║ data3  ║ data5  ║     2 ║
║ data10 ║ data11 ║ data12 ║ data13 ║     3 ║
║ data10 ║ data11 ║ data12 ║ data14 ║     3 ║
║ data10 ║ data11 ║ data12 ║ data15 ║     3 ║
╚════════╩════════╩════════╩════════╩═══════╝

Here is a sqlfiddle及其演示。

<强>更新如果您需要根据COUNT列进行过滤，则可以使用派生表或CTE：

派生表：

SELECT *
FROM (  SELECT col1, col2, col3, col4, COUNT(*) OVER(PARTITION BY col1) [Count]
        FROM Table1) A
WHERE [Count] > 2

CTE：

;WITH CTE AS
(
    SELECT col1, col2, col3, col4, COUNT(*) OVER(PARTITION BY col1) [Count]
    FROM Table1
)
SELECT *
FROM CTE 
WHERE [Count] > 2

结果：

╔════════╦════════╦════════╦════════╦═══════╗
║  COL1  ║  COL2  ║  COL3  ║  COL4  ║ COUNT ║
╠════════╬════════╬════════╬════════╬═══════╣
║ data10 ║ data11 ║ data12 ║ data13 ║     3 ║
║ data10 ║ data11 ║ data12 ║ data14 ║     3 ║
║ data10 ║ data11 ║ data12 ║ data15 ║     3 ║
╚════════╩════════╩════════╩════════╩═══════╝

sqlfiddle with this option

计算每个组返回的记录数

1 个答案: