Delegation Rules: GROUP BY

GROUP BY is an operations on the SELECT clause. The following rules apply to what can be delegated to the data source provider:

  1. GROUP BY can be delegated to a data source provider if the data provider supports it.
  2. GROUP BY can be delegated only when it contains a column name or alias. If there is more than one column in the GROUP BY, the left-most column will be delegated
  3. GROUP BY cannot be delegated if a GROUP BY expression contains a function or operator.
  4. If the data source provider does not support GROUP BY but does support ORDER BY then the column for the GROUP BY will be delegated to the data source provider in an ORDER BY.