Question

我试图从SQL查询中一次抓取100行并将它们用于分页。该查询从具有100,000多行的表中返回~2000行。但是，该表没有唯一标识符。

SELECT TOP 100 * FROM tbl_Items WHERE tbl_Items.Repair_Required = true

我已经研究过使用ROW_NUMBER，但似乎在MS Access中不可用。我还研究了使用＆＃34; self-join＆＃34;创建自定义row_number。正如戈德·汤普森在这里所回答的那样：Access query producing results like ROW_NUMBER() in T-SQL。但是，加入我自己的100,000多个表并不容易。

我有什么选择？

Answer 1

这是一个使用集合的方法，它的工作非常快：

Public Function RowCounter( _
  ByVal strKey As String, _
  ByVal booReset As Boolean, _
  Optional ByVal strGroupKey As String) _
  As Long

' Builds consecutive RowIDs in select, append or create query
' with the possibility of automatic reset.
' Optionally a grouping key can be passed to reset the row count
' for every group key.
'
' Usage (typical select query):
'   SELECT RowCounter(CStr([ID]),False) AS RowID, *
'   FROM tblSomeTable
'   WHERE (RowCounter(CStr([ID]),False) <> RowCounter("",True));
'
' The Where statement resets the counter when the query is run
' and is needed for browsing a select query.
'
' Usage (typical append query, manual reset):
' 1. Reset counter manually:
'   Call RowCounter(vbNullString, False)
' 2. Run query:
'   INSERT INTO tblTemp ( RowID )
'   SELECT RowCounter(CStr([ID]),False) AS RowID, *
'   FROM tblSomeTable;
'
' Usage (typical append query, automatic reset):
'   INSERT INTO tblTemp ( RowID )
'   SELECT RowCounter(CStr([ID]),False) AS RowID, *
'   FROM tblSomeTable
'   WHERE (RowCounter("",True)=0);
'
' 2002-04-13. Cactus Data ApS. CPH
' 2002-09-09. Str() sometimes fails. Replaced with CStr().
' 2005-10-21. Str(col.Count + 1) reduced to col.Count + 1.
' 2008-02-27. Optional group parameter added.

  Static col      As New Collection
  Static strGroup As String

  On Error GoTo Err_RowCounter

  If booReset = True Or strGroup <> strGroupKey Then
    Set col = Nothing
    strGroup = strGroupKey
  Else
    col.Add col.Count + 1, strKey
  End If

  RowCounter = col(strKey)

Exit_RowCounter:
  Exit Function

Err_RowCounter:
  Select Case Err
    Case 457
      ' Key is present.
      Resume Next
    Case Else
      ' Some other error.
      Resume Exit_RowCounter
  End Select
End Function

请研究内嵌评论和示例。

当然，您可以将它应用于具有2000条记录的查询，而不是源表。

MS Access SQL分页与查询（没有唯一标识符）或ROW_NUMBER？

1 个答案: