QueryDef.SQL Property (DAO)

Sets or returns the SQL statement that defines the query executed by a QueryDef object.

Syntax

expression .SQL

expression A variable that represents a QueryDef object.

Remarks

The SQL property contains the SQL statement that determines how records are selected, grouped, and ordered when you execute the query. You can use the query to select records to include in a Recordset object. You can also define action queries to modify data without returning records.

The SQL syntax used in a query must conform to the SQL dialect of the query engine, which is determined by the type of workspace. In a Microsoft Access workspace, use the Microsoft Access SQL dialect, unless you create an SQL pass-through query, in which case you should use the dialect of the server.

If the SQL statement includes parameters for the query, you must set these before execution. Until you reset the parameters, the same parameter values are applied each time you execute the query.

In a Microsoft Access workspace, using a QueryDef object is the preferred way to perform SQL pass-through operations on Microsoft Access database engine-connected ODBC data sources. By setting the QueryDef object's Connect property to an ODBC data source, you can use non–Microsoft–Access–database SQL in the query to be passed to the external server. For example, you can use TRANSACT SQL statements (with Microsoft SQL Server or Sybase SQL Server databases), which the Microsoft Access database engine would otherwise not process.

Note

If you set the property to a string concatenated with a non-integer value, and the system parameters specify a non-U.S. decimal character such as a comma (for example, strSQL = "PRICE > " & lngPrice, and lngPrice = 125,50), an error will result when you try to execute the QueryDef object in a Microsoft Access database engine database. This is because during concatenation, the number will be converted to a string using your system's default decimal character, and Microsoft Access SQL only accepts U.S. decimal characters.

Example

This example demonstrates the SQL property by setting and changing the SQL property of a temporary QueryDef and comparing the results. The SQLOutput function is required for this procedure to run.

Sub SQLX() 
 
   Dim dbsNorthwind As Database 
   Dim qdfTemp As QueryDef 
   Dim rstEmployees As Recordset 
 
   Set dbsNorthwind = OpenDatabase("Northwind.mdb") 
   Set qdfTemp = dbsNorthwind.CreateQueryDef("") 
 
   ' Open Recordset using temporary QueryDef object and  
   ' print report. 
   SQLOutput "SELECT * FROM Employees " & _ 
      "WHERE Country = 'USA' " & _ 
      "ORDER BY LastName", qdfTemp 
 
   ' Open Recordset using temporary QueryDef object and  
   ' print report. 
   SQLOutput "SELECT * FROM Employees " & _ 
      "WHERE Country = 'UK' " & _ 
      "ORDER BY LastName", qdfTemp 
 
   dbsNorthwind.Close 
 
End Sub 
 
Function SQLOutput(strSQL As String, qdfTemp As QueryDef) 
 
   Dim rstEmployees As Recordset 
 
   ' Set SQL property of temporary QueryDef object and open  
   ' a Recordset. 
   qdfTemp.SQL = strSQL 
   Set rstEmployees = qdfTemp.OpenRecordset 
 
   Debug.Print strSQL 
 
   With rstEmployees 
      ' Enumerate Recordset. 
      Do While Not .EOF 
         Debug.Print "  " & !FirstName & " " & _ 
            !LastName & ", " & !Country 
         .MoveNext 
      Loop 
      .Close 
   End With 
 
End Function 

This example uses the CopyQueryDef method to create a copy of a QueryDef from an existing Recordset and modifies the copy by adding a clause to the SQL property. When you create a permanent QueryDef, spaces, semicolons, or linefeeds may be added to the SQL property; these extra characters must be stripped before any new clauses can be attached to the SQL statement.

Function CopyQueryNew(rstTemp As Recordset, _ 
   strAdd As String) As QueryDef 
 
   Dim strSQL As String 
   Dim strRightSQL As String 
 
   Set CopyQueryNew = rstTemp.CopyQueryDef 
   With CopyQueryNew 
      ' Strip extra characters. 
      strSQL = .SQL 
      strRightSQL = Right(strSQL, 1) 
      Do While strRightSQL = " " Or strRightSQL = ";" Or _ 
            strRightSQL = Chr(10) Or strRightSQL = vbCr 
         strSQL = Left(strSQL, Len(strSQL) - 1) 
         strRightSQL = Right(strSQL, 1) 
      Loop 
      .SQL = strSQL & strAdd 
   End With 
 
End Function 
 
This example shows a possible use of CopyQueryNew(). 
 
Sub CopyQueryDefX() 
 
   Dim dbsNorthwind As Database 
   Dim qdfEmployees As QueryDef 
   Dim rstEmployees As Recordset 
   Dim intCommand As Integer 
   Dim strOrderBy As String 
   Dim qdfCopy As QueryDef 
   Dim rstCopy As Recordset 
 
   Set dbsNorthwind = OpenDatabase("Northwind.mdb") 
   Set qdfEmployees = dbsNorthwind.CreateQueryDef( _ 
      "NewQueryDef", "SELECT FirstName, LastName, " & _ 
      "BirthDate FROM Employees") 
   Set rstEmployees = qdfEmployees.OpenRecordset( _ 
      dbOpenForwardOnly) 
 
   Do While True 
      intCommand = Val(InputBox( _ 
         "Choose field on which to order a new " & _ 
         "Recordset:" & vbCr & "1 - FirstName" & vbCr & _ 
         "2 - LastName" & vbCr & "3 - BirthDate" & vbCr & _ 
         "[Cancel - exit]")) 
      Select Case intCommand 
         Case 1 
            strOrderBy = " ORDER BY FirstName" 
         Case 2 
            strOrderBy = " ORDER BY LastName" 
         Case 3 
            strOrderBy = " ORDER BY BirthDate" 
         Case Else 
            Exit Do 
      End Select 
      Set qdfCopy = CopyQueryNew(rstEmployees, strOrderBy) 
      Set rstCopy = qdfCopy.OpenRecordset(dbOpenSnapshot, _ 
         dbForwardOnly) 
      With rstCopy 
         Do While Not .EOF 
            Debug.Print !LastName & ", " & !FirstName & _ 
               " - " & !BirthDate 
            .MoveNext 
         Loop 
         .Close 
      End With 
      Exit Do 
   Loop 
 
   rstEmployees.Close 
   ' Delete new QueryDef because this is a demonstration. 
   dbsNorthwind.QueryDefs.Delete qdfEmployees.Name 
   dbsNorthwind.Close 
 
End Sub 

This example uses the CreateQueryDef and OpenRecordset methods and the SQL property to query the table of titles in the Microsoft SQL Server sample database Pubs and return the title and title identifier of the best-selling book. The example then queries the table of authors and instructs the user to send a bonus check to each author based on his or her royalty share (the total bonus is $1,000 and each author should receive a percentage of that amount).

Sub ClientServerX2() 
 
   Dim dbsCurrent As Database 
   Dim qdfBestSellers As QueryDef 
   Dim qdfBonusEarners As QueryDef 
   Dim rstTopSeller As Recordset 
   Dim rstBonusRecipients As Recordset 
   Dim strAuthorList As String 
 
   ' Open a database from which QueryDef objects can be  
   ' created. 
   Set dbsCurrent = OpenDatabase("DB1.mdb") 
 
   ' Create a temporary QueryDef object to retrieve 
   ' data from a Microsoft SQL Server database. 
   Set qdfBestSellers = dbsCurrent.CreateQueryDef("") 
   With qdfBestSellers 
      ' Note: The DSN referenced below must be configured to  
      '       use Microsoft Windows NT Authentication Mode to  
      '       authorize user access to the Microsoft SQL Server. 
      .Connect = "ODBC;DATABASE=pubs;DSN=Publishers" 
      .SQL = "SELECT title, title_id FROM titles " & _ 
         "ORDER BY ytd_sales DESC" 
      Set rstTopSeller = .OpenRecordset() 
      rstTopSeller.MoveFirst 
   End With 
 
   ' Create a temporary QueryDef to retrieve data from 
   ' a Microsoft SQL Server database based on the results from 
   ' the first query. 
   Set qdfBonusEarners = dbsCurrent.CreateQueryDef("") 
   With qdfBonusEarners 
      ' Note: The DSN referenced below must be configured to  
      '       use Microsoft Windows NT Authentication Mode to  
      '       authorize user access to the Microsoft SQL Server. 
      .Connect = "ODBC;DATABASE=pubs;DSN=Publishers" 
      .SQL = "SELECT * FROM titleauthor " & _ 
         "WHERE title_id = '" & _ 
         rstTopSeller!title_id & "'" 
      Set rstBonusRecipients = .OpenRecordset() 
   End With 
 
   ' Build the output string. 
   With rstBonusRecipients 
      Do While Not .EOF 
         strAuthorList = strAuthorList & "  " & _ 
            !au_id & ":  $" & (10 * !royaltyper) & vbCr 
         .MoveNext 
      Loop 
   End With 
 
   ' Display results. 
   MsgBox "Please send a check to the following " & _ 
      "authors in the amounts shown:" & vbCr & _ 
      strAuthorList & "for outstanding sales of " & _ 
      rstTopSeller!Title & "." 
 
   rstTopSeller.Close 
   dbsCurrent.Close 
 
End Sub 

The following example shows how to create a parameter query. A query named myQuery is created with two parameters, named Param1 and Param2. To do this, the SQL property of the query is set to a Structured Query Language (SQL) statement that defines the parameters.

Sample code provided by: The Microsoft Access 2010 Programmer’s Reference | About the Contributors

Sub CreateQueryWithParameters()

    Dim dbs As DAO.Database
    Dim qdf As DAO.QueryDef
    Dim strSQL As String

    Set dbs = CurrentDb
    Set qdf = dbs.CreateQueryDef("myQuery")
    Application.RefreshDatabaseWindow

    strSQL = "PARAMETERS Param1 TEXT, Param2 INT; "
    strSQL = strSQL & "SELECT * FROM [Table1] "
    strSQL = strSQL & "WHERE [Field1] = [Param1] AND [Field2] = [Param2];"
    qdf.SQL = strSQL

    qdf.Close
    Set qdf = Nothing
    Set dbs = Nothing

End Sub

The following example shows how to replace the Structured Query Language (SQL) statement in a saved query.

Dim qdf as QueryDef
Dim db as Database
Set db = CurrentDB
Set qdf = db.QueryDefs(“YourQueryName”)
qdf.SQL = ReplaceWhereClause(qdf.SQL, strYourNewWhereClause)
set qdf = Nothing
set db = Nothing

Public Function ReplaceWhereClause(strSQL As Variant, strNewWHERE As Variant)
On Error GoTo Error_Handler

‘This subroutine accepts a valid SQL string and Where clause, and
‘returns the same SQL statement with the original Where clause (if any)
‘replaced by the passed in Where clause.
‘
‘INPUT:
‘ strSQL valid SQL string to change
‘OUTPUT:
‘ strNewWHERE New WHERE clause to insert into SQL statement
‘
Dim strSELECT As String, strWhere As String
Dim strOrderBy As String, strGROUPBY As String, strHAVING As String

Call ParseSQL(strSQL, strSELECT, strWhere, strOrderBy, _
strGROUPBY, strHAVING)

ReplaceWhereClause = strSELECT &“”& strNewWHERE &“”_
& strGROUPBY &“”& strHAVING &“”& strOrderBy

Exit_Procedure:
  Exit Function

Error_Handler:
  MsgBox (Err.Number & “: “ & Err.Description)
  Resume Exit_Procedure

End Function

About the Contributors

Wrox Press is driven by the Programmer to Programmer philosophy. Wrox books are written by programmers for programmers, and the Wrox brand means authoritative solutions to real-world programming problems.