Microsoft Access 2010 Bible

Chapter 25: Advanced Data Access with VBA

891

FIGURE 25.8

Running the parameter query

Tip
You can use the wildcards * (anything after this position) and? (one character in this position) with a Like
operator in any query or SQL string.

Note
If SQL Server Compatible Syntax (ANSI 92) is selected (File ➪ Options, then select the Object Designers tab),
or if ADO is being used to run the SQL statement, the wildcards are % (anything in this position) and _ (one
character in this position)

A consequence of adding the asterisk to the parameter is that, if the user doesn’t enter a parameter

value, the criteria evaluates to “LIKE *”, and the query returns all records. Leaving the asterisk

out of the criteria expression results in no returned records if the user fails to provide a product

category.

Figure 25.9 shows the Query Parameters dialog box (opened by right-clicking the query’s upper

area and selecting Parameters from the shortcut menu). You use the Query Parameters dialog box

to specify parameters that require special consideration, such as date/time entries or specially for-

matted numbers. One text entry has been entered in the Query Parameters dialog box to show how

it works. You enter the parameter text and choose the parameter’s data type.