How can group sum be performed on a join query when one side of the join is empty?

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If one side of the join is empty, the result of the join will have NULL values for columns on the empty side. When performing a group sum on the joined query, the NULL values will be ignored and not included in the calculation. Therefore, the result of the group sum may be inaccurate or incorrect due to the missing data.

To handle this scenario, it may be necessary to use alternative techniques such as a conditional statement or subquery to derive appropriate values for the missing data. Alternatively, it may be necessary to adjust the join criteria to include all relevant data regardless of whether there is a match.