CreateQuery t_index_agg_func (children 3)
 Identifier t_index_agg_func
 Columns definition (children 1)
  ExpressionList (children 2)
   ColumnDeclaration id (children 1)
    DataType UInt64
   ColumnDeclaration v (children 1)
    DataType AggregateFunction (children 1)
     ExpressionList (children 2)
      Identifier avg
      DataType UInt64
 Storage definition (children 3)
  Function AggregatingMergeTree
  Identifier id
  Set
