Verify Lookup Keys (Lookup Function)

You can use the Lookup function to verify that a key value exists in a lookup table. You can specify the Lookup function in condition expressions only. Specify the Lookup function as the expression for the term whose value is the lookup key that you want to search for. The syntax of the Lookup function is as follows:

Lookup ("lookup_table_name")

For lookup_table_name, specify the name of the lookup table that you want to search.

For example, if you want to verify that the value of the term Ctry_Key exists as a key value in the table Country_Codes, enter the Lookup function as the expression for the Ctry_Key term as shown in the following display.

Image Showing the Example Lookup(“country_codes”)

The Lookup function returns a value of True or False, depending on whether the key value exists in the lookup table. For example, suppose the Ctry_Key column in the current input record contains the value “CA”. If the Country_Codes lookup table contains the lookup key “CA”, then the expression shown in the display above evaluates to True.

Note: If an expression contains the Lookup function, then the expression cannot contain anything else.