QueryDef.SQL Property (DAO)
Last modified: July 01, 2011
Applies to: Access 2013 | Office 2013
Sets or returns the SQL statement that defines the query executed by a QueryDef object.
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.
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.
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.
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