This article shows you how to use a form to specify the
criteria for a query. This technique is called query by form (QBF).
In the QBF technique, you create a form in which you enter
query criteria. This form contains blank text boxes. Each text box represents a
field in a table that you want to query. You make entries only in the text
boxes for which you want to specify search criteria.
The QBF form
resembles a data entry form that has fields that match the fields in a table. A
table that has fields for Name, Address, City, State, and ZIP Code can have a
QBF form that has corresponding fields. To select certain records, you can
enter any combination of search criteria in the form. You can specify a city
only, or a city and a state, or a ZIP code only, or any other combination.
Fields that you leave blank are ignored. When you click a command button on the
form, Access runs a query that uses the search criteria from your
To use the QBF technique, follow these steps:
- Open the sample database Northwind.mdb.
- Create a new form that is not based on any table or query,
and save it as QBF_Form.
- On the new form, create two text boxes and one command
button that has the following properties. Then, save the form:
Text box 1
Text box 2
Command button 1:
- Create the following new macro, and then save it as
Query Name: QBF_Query
Data Mode: Edit
- Create the following new query that is based on the Orders
table, and then save it as QBF_Query:
Criteria: Forms![QBF_Form]![WhatCustomer] Or Forms![QBF_Form]![WhatCustomer] Is Null
Criteria: Forms![QBF_Form]![WhatEmployee] Or Forms![QBF_Form]![WhatEmployee] Is Null
NOTE: When you type the criteria, make sure that you
type the entire criteria in a single Criteria field;
do not split the criteria by placing the 'Or' section
on a separate row.
- Open QBF_Form in the Form view. Enter the following
combinations of criteria. Click Search after each combination:
Customer ID Employee ID Result
<blank> <blank> All 830 orders
AROUT <blank> 13 orders
AROUT 4 4 AROUT orders for employee 4
<blank> 4 156 orders for employee 4
After you view the result set for each query, close the
Datasheet window. Then, begin your next search. Each time that you click the Search
button, the parameters in the QBF query filter the data based on
the search criteria that you specified on the QBF query form.
Notes on the QBF parameter criteria
The sample QBF query in this article implements criteria in the
Forms!FormName!ControlName Or Forms!FormName!ControlName Is Null
to filter the data. These criteria return all
matching records. If the criteria value is null, all the records are returned
for the specified field.
You can specify any of the following
alternative criteria to return slightly different results.NOTE
: In the following sample criteria, an underscore (_) is used as a
line-continuation character. Remove the underscore from the end of the line
when you re-create these criteria.
- Like Forms!FormName!ControlName & "*" Or _
Forms!FormName!ControlName Is Null
This criteria statement is the same as the QBF sample
above, except that you can query by using a wildcard. For example, if you enter
"Jo" in a field by using this criteria statement, the query returns every
record in the field that begins with "Jo." This includes Johnson, Jones,
Johanna, and so on.
- Between Forms!FormName!StartDate And Forms!FormName!EndDate Or _
Forms!FormName!StartDate Is Null You can use this criteria statement to query a date field by
using Start Date and End Date text boxes on the query form. Records whose start and end dates
fall between the values that you specify on the query form are returned. If you
omit a Start Date value on the form, however, the query returns all records,
regardless of the End Date value.
- Like Forms!FormName!ControlName & "*" Or Is Null
This criteria statement returns both records that match
the criteria and records that are null. If the criteria are null, all the
records are returned. Note that the asterisk (*) is considered a parameter
because it is part of a larger Like expression. Because the asterisk is a
hard-coded criteria value (for example, Like "*"), records with null values are
- Like IIf(IsNull(Forms!FormName![ControlName]), _
This criteria statement returns all the records that
match the criteria. If no criteria are specified in the query form, all records
that are not null are returned.
- IIf(IsNull(Forms!FormName![ControlName]), _
This returns all the records that match the criteria.
If no criteria are specified in the query form, all records that are not null are returned (the same result as in the example
information about parameter queries, click the following article numbers to
view the articles in the Microsoft Knowledge Base:
How to create a parameter In() statement
Showing all records (including null) in a parameter query
Article ID: 304428 - Last Review: March 27, 2007 - Revision: 7.1
- Microsoft Office Access 2007
- Microsoft Office Access 2003
- Microsoft Access 2002 Standard Edition