A field expression represents the value of a field. Create a field expression to change the value, datatype, scale, or precision of a field.
For example, you perform a case-sensitive comparison between the field values of the LAST_NAME fields in two tables. The first table contains values with lowercase letters. The second table contains values with uppercase letters. To match the field values, you convert the uppercase letters in the second table to lowercase. You enter the following field expression for the field of the second table:
You can include field expressions in join conditions for table pairs, join views or aggregate views or in source-to-lookup relationships for lookup views.
When you create a field expression, you also specify the datatype, precision, and scale of the expression result. You must ensure that the datatype, precision, and scale of the field expression are valid. For example, you create a join condition between a field and a field expression. The datatype of the field expression must be compatible with the datatype of the other field in the join condition.