It's documented in VFP8 help under Behavior Changes Since Visual FoxPro 7.0 and INFO: SQL SELECT Behavior Changes in Visual FoxPro 8.0 mskb #813361.

>Did any one use GROUP BY for SELECT - SQL? Why I alway get error message invalid GROUP BY? I think the VFP 8.0 is broken product I try convert my applications from VFP6.0 to VFP8.0 none of them work anymore.
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>Thanks, Tai Fei Pao