Custom SQL Query - Unable to find Primary Key for Table

9. I do not get any output for custom SQL Query i added and i am getting an error "Unable to find the primary key for Table. Please use the "Primary Keys" option in that table to select a primary key and to access the query output"

Reason  : SQLDBManager Plus is unable to find the primary keys for the query provided
Solution : In the Query tab, click on the "Primary Keys" link above the corresponding table and select the Unique column from the list there. If the query does not have a unique column, modify the query and add a new unique column by using row_number() or rank() functions and select this column as primary key