SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 2)
   ExpressionList (children 1)
    Function sumMap (children 1)
     ExpressionList (children 2)
      Identifier val
      Identifier cnt
   TablesInSelectQuery (children 1)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      Subquery (children 1)
       SelectWithUnionQuery (children 1)
        ExpressionList (children 1)
         SelectQuery (children 1)
          ExpressionList (children 2)
           Function array (alias val) (children 1)
            ExpressionList (children 2)
             Function CAST (children 1)
              ExpressionList (children 2)
               Literal \'a\'
               Literal \'FixedString(1)\'
             Function CAST (children 1)
              ExpressionList (children 2)
               Literal \'b\'
               Literal \'FixedString(1)\'
           Literal Array_[UInt64_1, UInt64_2] (alias cnt)
