Question

在SQL Server 2005中，我创建一个查询，生成具有以下属性的结果集：

TableName | ColumnName | SomeColumn

我可以以某种方式增强此查询，以便对于来自该结果集的每条记录，我会得到count of elements from that table（或者通常对TableName，ColumnName上指定的表和列执行任何查询吗？可以实现这样的事情吗？：

SELECT *, (SELECT COUNT(*) FROM Q.TableName) AS Cnt, (SELECT AVG(SomeColumn) FROM Q.TableName) AS AvgValue

FROM 
(`...OMITTED ORIGINAL QUERY...`) AS Q

以上查询无效。发生错误：＆＃34;无效的对象名称＆Q; .TableName＆＃39;＆＃34;。

在SQL Server 2005中是否可以使用简单查询（没有存储过程）？

示例数据：

TableName | ColumName 

SomeTable1 | Column11
SomeTable1 | Column12
SomeTable2 | Column21
SomeTable2 | Column22
SomeTable3 | Column31

我希望sample data中的每一行都有更多属性：

TableName | ColumName | CountInThatTable | AvgValueInThatColumnFromThatTable

SomeTable1 | Column11 | N1               | N11
SomeTable1 | Column12 | N1               | N12
SomeTable2 | Column21 | N2               | N21
SomeTable2 | Column22 | N2               | N22
SomeTable3 | Column31 | N3               | N31

Answer 1

如果我正确理解您的问题，那么要获得结果，您需要动态查询。以下是您可以用来实现结果的示例。

DECLARE @TableName VARCHAR(100)
CREATE TABLE #tblRowCount (Id INT IDENTITY(1,1),
                           TableName VARCHAR(100), 
                           NoOfRows int)
DECLARE cur_trav  CURSOR FOR SELECT Name FROM sys.tables
OPEN cur_trav
FETCH NEXT FROM cur_Trav INTO @tableName
DECLARE @SQL VARCHAR(5000)

WHILE @@FETCH_STATUS =0
BEGIN
SET @SQL =''
SET @SQL = ' INSERT INTO #tblRowCount (tableName, NoOfRows)  SELECT ''' + @TableName +''' as tableName , COUNT(1) as counter FROM ' + @TableName 
EXECUTE(@SQL)
--  --PRINT @sql
  FETCH NEXT FROM cur_Trav  
END 
CLOSE cur_Trav
DEALLOCATE cur_trav

SELECT Id,tableName, NoOfRows FROM #tblRowCount
DROP TABLE #tblRowCount

Answer 2

如果要查询返回的行数，请在每行的单独列中使用窗口函数：

select . . .,
       count(*) over () as overall_cnt
from . . .;

从查询

2 个答案: