SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 2)
   ExpressionList (children 3)
    Function avg (children 1)
     ExpressionList (children 1)
      Identifier a
    Function avg (children 1)
     ExpressionList (children 1)
      Identifier b
    Function count (children 1)
     ExpressionList
   TablesInSelectQuery (children 1)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      TableIdentifier t_proj
