sourceField - the field from which the lookup value is taken.

failExpression - any expression.

Parameters in braces { } are optional.

text, number, date, time, timestamp, container

The result of the optional failExpression is returned if the lookup fails.

For this function to access the contents of the source field, the tables containing the source field and calculation field need to be related. Calculations using the Lookup function won’t be forced to be unstored calculations.

There are two tables, People and Company, in a database file containing the data shown below.

The People and Company tables are related using the number field CompanyID. The calculation CompanyName = Lookup ( Company::CompanyName ; "Not found" ) defined in the People table will return Apple for the first record, FileMaker for the second record, and Not found for the third record.