Line graph displays the error, 'Query Execution Failed ! :Ambiguous column name 'DATE_KEY'. Why?

Line graph displays the error, 'Query Execution Failed ! :Ambiguous column name 'DATE_KEY'. Why?

This error occurs if the column name is not defined properly. Illustration: --------------- The 'orderByDes' attribute - "DATE_KEY" might not be enclosed within '#' i.e. It should be defined as '#DATE_KEY#' For all the Dimension levels (For e.g. DATE_KEY) where orderByDes is defined, it should be defined either as: a) "#DATE_KEY#" OR b) "DIM_DATE.DATE_KEY"