Is it possible to query a datastore entity to give result based on unique combination of two columns and group record values as separated by commas for other columns.

Is it possible to query a datastore entity to give result based on unique combination of two columns and group record values as separated by commas for other columns. For Ex:
Sr. no deal no. Description
123 abc Desc1
123 abc Desc2

Can I query this datastore it to return one record as follows:
123 abc Desc1, Desc2

OriginalPostID-198561

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