The new Results Difference tool provides a user with graphical representation depicting differences between two result sets obtained from either the same query or two different queries.

It is displayed as a table presenting differences in data structure and data, which allows a user to see what columns or rows have been added or deleted, and what cells have been edited in the second result set compared to the first result set. The rows are compared corresponding to a primary key picked by the user from the Primary Key tab.

Obtaining Result Sets - The result sets are obtained from the query analyzer panel results which include all open query analyzer tabs. The user is prompted to select two result sets from a dialog.

Refreshing Results Diff - The results difference is refreshed when a user changes the choice of primary keys, or clicks on the refresh button. In the latter case a user is prompted to select two new result sets from a dialog, and the result difference is loaded into the same Results Diff panel.

Progress status - As the results difference is being calculated, the progress of the calculation is shown on a progress bar.

Limitations: If a query returns multiple rows with the same primary keys, then there is no reliable way to identify modified rows in the result sets. Multiple rows for the same primary keys are obtained in 2 cases: due to user selection of the primary keys and to the selection of the query columns. Initially, Results Difference is run with all of the common columns selected as primary keys. In this case, if the query returns duplicate rows, it's due to query column selection. If a table has duplicate rows and no primary key defined, then there is no way to determine if those rows have been modified even though a user selects all of the table columns for the query and all of the common columns as primary keys. If this problem occurs, Results Difference is still run on the result sets using intelligent assumptions about what rows correspond to each other, but a user is warned about duplicate rows. If there are duplicate rows in the result sets on the initial run, then a user is advised to change column selection in the query. If there are duplicate rows obtained after a user changes the set of primary keys, then the user is advised to redefine the primary keys.