More about column-binding expressions
When you write an expression for a column binding, the expression can refer to data set fields, other column bindings, functions, and operators. Until you become familiar with writing expressions, you should use Expression Builder to construct expressions. Expression Builder displays the items—data set fields, column bindings, functions, and so on—that you can use in a column-binding expression.
The items available in Expression Builder change depending on where you define the column binding. For example, if you insert a data element in a table that contains other column bindings, the data element can access those column bindings. If you insert a data element directly on the report page, the data element cannot access column bindings defined for the table or any other report element.
When you select an item in Expression Builder, Expression Builder adds the item to the expression with the proper syntax. When a column-binding expression refers to a data set field, the syntax is:
When a column-binding expression refers to another column binding, the syntax is:
If you use Expression Builder to construct column-binding expressions, you do not need to remember what syntax to use. You will find it helpful, though, to understand what each syntax means, because the expression examples that appear throughout the book use both syntaxes.