Question

所以我试图解决的问题是我有8个包含数据的表。还有一个第9个表，每个表都有一个字段，我想存储前8个表中每个表的计数。我能够返回计数但不是每个字段有一个计数，我只有8行填充第一个字段。 8个表名中的每一个都是第9个表中的字段名。这是我的代码：

SELECT COUNT(SubID) as Sent_Members FROM Sent_Members
UNION ALL
SELECT COUNT(SubID) as Sent_Shoppers FROM Sent_Shoppers
UNION ALL
SELECT COUNT(SubID) as Open_Members FROM Open_Members
UNION ALL
SELECT COUNT(SubID) as Open_Shoppers FROM Open_Shoppers
UNION ALL
SELECT COUNT(SubID) as Click_Members FROM Click_Members
UNION ALL
SELECT COUNT(SubID) as Click_Shoppers FROM Click_Shoppers
UNION ALL
SELECT COUNT(SubID) as Unique_Click_Members FROM Unique_Click_Members
UNION ALL
SELECT COUNT(SubID) as Unique_Click_Shoppers FROM Unique_Click_Shoppers

我猜我应该使用的东西而不是Union，但我不确定那会是什么......谢谢！

Answer 1

这看起来更加丑陋，但它比每个子查询完成8个子查询的效率高出数百倍。

;WITH r AS
(
  SELECT t.name, rc = SUM(p.rows)
   FROM sys.tables AS t
   INNER JOIN sys.partitions AS p
   ON t.[object_id] = p.[object_id]
   WHERE p.index_id IN (0,1)
   AND t.name IN 
   (
    N'Sent_Members',
    N'Sent_Shoppers',
    N'Open_Members',
    N'Open_Shoppers',
    N'Click_Members',
    N'Click_Shoppers',
    N'Unique_Click_Members',
    N'Unique_Click_Shoppers'
   )
   GROUP BY t.name
)
SELECT * FROM r 
PIVOT (MAX(rc) FOR name IN 
(
 [Sent_Members],
 [Sent_Shoppers],
 [Open_Members],
 [Open_Shoppers],
 [Click_Members],
 [Click_Shoppers],
 [Unique_Click_Members],
 [Unique_Click_Shoppers]
) AS p;

Answer 2

你走了：

INSERT INTO [Table9]
SELECT 
    (SELECT COUNT(*) FROM Sent_Members) AS Sent_Members,
    (SELECT COUNT(*) FROM Sent_Shoppers) AS Sent_Shoppers,
    (SELECT COUNT(*) FROM Open_Members) AS Open_Members,
    (SELECT COUNT(*) FROM Open_Shoppers) AS Open_Shoppers,
    (SELECT COUNT(*) FROM Click_Members) AS Click_Members,
    (SELECT COUNT(*) FROM Click_Shoppers) AS Click_Shoppers,
    (SELECT COUNT(*) FROM Unique_Click_Members) AS Unique_Click_Members,
    (SELECT COUNT(*) FROM Unique_Click_Shoppers) AS Unique_Click_Shoppers

从多个表中选择Count并将它们全部返回到一行 - SQL Server

2 个答案: