Question

我有一个问题，我需要确定有多少公司参与了给定的项目编号。例如，确定哪些公司恰好参与了2个项目。

给出下面的基数：

Option Explicit

Sub Export_to_TXT_UTF16()

Dim saveas_filename As Variant
saveas_filename = Application.GetSaveAsFilename(FileFilter:="Unicode Text (*.txt), *.txt", Title:="SaveAs")
If saveas_filename = False Then
    Exit Sub
End If

With Application
    .ScreenUpdating = False
    .DisplayAlerts = False
End With

ActiveSheet.Copy

With ActiveSheet.UsedRange
    .Value = .Value
End With

Rows(1).Delete          'DELETE ROW #1

Columns("C:G").Delete       'DELETE COLUMNS C-G

ActiveWorkbook.SaveAs Filename:=saveas_filename, FileFormat:=xlUnicodeText

ActiveWorkbook.Close SaveChanges:=False

With Application
    .ScreenUpdating = True
    .DisplayAlerts = True
End With

MsgBox "Your data has been exported!", vbExclamation, "Sheet Exported"

End Sub

如何使用SQL查询解决此问题？对于上述情况，查询将返回：

id company project  
1 company1 project1
2 company2 project1
3 company3 project2
4 company1 project2
5 company2 project2
6 company2 project3
7 company3 project1
8 company1 project1
9 company2 project2
10 company1 project2

Answer 1

您可以使用company来聚合，并使用having子句进行过滤：

select company
from mytable
group by company
having count(project) = 2

如果同一项目对于给定的公司可能发生两次，那么您希望使用count(distinct project)而不是count(project)。

Answer 2

您使用group by和having：

select company
from t
group by company
having count(distinct project) = 2;

计数SQL查询记录

2 个答案: