To use a column in a query, you must add it to the query. You may add a column to display it in query output, to use it for sorting, to search the contents of the column, or to summarize its contents.
In the Diagram Pane, select the checkbox next to the column that you want to include.
Alternatively
In the Tabbed Editor, move to the first blank grid row, click the field in the Column column, and select a table and a column name from the drop-down list.