Join Split Array Functions-2
This is the continuation of last week’s Article: Join Split Array Functions
If you have not gone through the fundamentals of the above functions then please do that, by following the above link, before continuing.
Since, Join() and Split() Functions are related, It is time to try out a real world example with them. It may not be the easiest solution to the problem we are trying to solve, but it will help to understand these functions' usage better.
- Import Employees Table from the Northwind sample database: C:\Program Files\Microsoft Office\Office11\samples\Northwind.mdb
- Open a new Query in SQL View (don't select any Table from the displayed list).
- Copy and paste the following SQL string into the SQL editing window and save the Query with the name EmployeeSelectQ.
SELECT Employees.* FROM Employees;
- Design a new Form like the sample image giving below (you may use the Form Wizard to quickly create the Form) using EmployeeSelectQ Query as Record Source.
- Add a Text Box and a Command Button at the bottom of the design.
- Select the Text Box and display the Property Sheet (View - ->Properties or Design - ->Property Sheet in 2007).
- Change the Name Property Value to txtCodes.
- Select the Command Button, change the Name Property value to cmdFilter and the Caption Property value to Apply Filter.
- Select the Child label of the Text Box and change its Caption value to Employee Codes:.
- Display the VBA Code Module of the Form (View – ->Code or click View Code toolbar button from Design Menu of 2007).
- Copy and paste the following VBA Code into the Form Module and save the Form with the name EmployeeSelect:
Private Sub cmdFilter_Click() Dim txt_Codes As String, varList As Variant Dim varCodes As Variant, j As Integer, x Dim maxCodes As Variant, invalid_Codes As String txt_Codes = Nz(Me.txtCodes, "") maxCodes = DMax("EmployeeID", "Employees") If Len(txt_Codes) = 0 Then varList = Null Else 'Split the items into the array. '(Here Array() Function will not work 'becuase the values in txtCodes variable is a String 'and will be treated as a single item). varCodes = Split(txt_Codes, ",") 'Validation check invalid_Codes = "" For j = 0 To UBound(varCodes) x = Val(varCodes(j)) If x < 1 Or x > maxCodes Then invalid_Codes = invalid_Codes & Format(x, "0 ") End If Next If Len(invalid_Codes) > 0 Then MsgBox "Invalid Employee Codes: " & invalid_Codes & vbCr & vbCr & "Correct and retry." Exit Sub End If 'here "varList = txt_Codes" is also works 'because txt_Codes values are separated with commas already varList = Join(varCodes, ",") End If 'Call the EmployeeFilter() function EmployeeFilter varList Me.RecordSource = "EmployeeSelectQ" Me.Requery End Sub
- Press Alt+F11 to open the VBA Editing window, if you have already closed it, select Module from Insert Menu to add a new Standard Module.
- Copy and paste the following VBA Code of EmployeeFilter() Function into the Standard Module and save it:
Public Function EmployeeFilter(ByVal Criteria As Variant) Dim strsql0 As String, sql As String Dim db As Database, qryDef As QueryDef strsql0 = "SELECT Employees.* FROM Employees WHERE (((Employees.EmployeeID) In (" Set db = CurrentDb Set qryDef = db.QueryDefs("EmployeeSelectQ") If IsNull(Criteria) Or Len(Criteria) = 0 Then sql = "SELECT Employees.* FROM Employees;" Else Criteria = Criteria & ")));" sql = strsql0 & Criteria End If qryDef.SQL = sql db.QueryDefs.Refresh End Function
- Open the EmployeeSelect Form in normal view. The sample image of the Form is given below:
- Enter the EmployeeIDs 2,3,7 and click on the Apply Filter Command Button.
Now, the EmployeeSelect Form have only three records, with employee codes 2,3 & 7.
- Delete all the Text Box contents and click on the Apply Filter Command Button.
The filter action is now reversed and all the records of the Employee Table are now available on the Form. In other words it works like a Reset command when the Text Box is empty.
You may try with different EmployeeIDs list.
Date and Time Values