如何在MS Access中执行区分大小写的分组

Question

In MS Access database to find the mismatch (ie difference) records between two tables(Employee and Employee_PROD) I am using the UNION ALL . The query is as follows:

SELECT [COMPANY],[DEPT],[DOJ],[EMP_ID],[Name],[SUB_COMPANY] FROM 

(SELECT '[Employee]' AS TableName,[COMPANY],[DEPT],[DOJ],[EMP_ID],[Name],[SUB_COMPANY] FROM [Employee] 

UNION ALL 

SELECT '[Employee_PROD]' AS TableName,[COMPANY],[DEPT],[DOJ],[EMP_ID],[Name],[SUB_COMPANY] FROM [Employee_PROD] ) 

GROUP BY [COMPANY],[DEPT],[DOJ],[EMP_ID],[Name],[SUB_COMPANY] 
HAVING COUNT(*) = 1 AND MIN(TableName) = '[Employee]'

The problem I am facing is that the GROUP BY is not considering the case sensitivity. For example " a ndrew" and " A ndrew" is treated as same. I want to perform group by with case sensitive to find the difference records.

Is there any way to do the same in MS Access?

Is there any other approach to find the differences between two tables having same column names, data types and the number of records is 7,00, 000?

I have tried the following:

• Load data to DataTable and then find the difference. Got out of memory exception due to huge amount of data.
• Use NOT EXISTS to compare the rows. The query got hanged and the execution never completed.
• The UNION ALL approach is working but the issue is that GROUP BY is not considering the case sensitivity.

Answer 1

You could group by the byte value:

? StrToByte("Andrew")
416E64726577
? StrToByte("andrew")
616E64726577

though it might be a bit slow with the large amount of data you have.

Public Function StrToByte(ByVal strChars As String) As String

  Dim abytChar()  As Byte
  Dim lngChar     As Long
  Dim strByte     As String

  abytChar() = StrConv(strChars, vbFromUnicode)

  strByte = Space(2 * (1 + UBound(abytChar) - LBound(abytChar)))
  For lngChar = LBound(abytChar) To UBound(abytChar)
    Mid(strByte, 1 + 2 * lngChar) = Hex(abytChar(lngChar))
  Next

  StrToByte = strByte

End Function

For SQL only, and if you only about the first character, try:

GROUP BY [COMPANY],[DEPT],[DOJ],[EMP_ID],[Name], ASC([Name]),[SUB_COMPANY] 

Answer 2

Can you not specify OPTION COMPARE BINARY in a module to perform a case sensitive search?

This thread https://access-programmers.co.uk/forums/showthread.php?t=33962 and this one How to write Case Sensitive Query for MS Access? both describe different methods.