SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 2)
   ExpressionList (children 1)
    Function uniqUpTo (children 2)
     ExpressionList (children 2)
      Identifier x
      Identifier x
     ExpressionList (children 1)
      Literal UInt64_3
   TablesInSelectQuery (children 1)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      Subquery (children 1)
       SelectWithUnionQuery (children 1)
        ExpressionList (children 1)
         SelectQuery (children 1)
          ExpressionList (children 1)
           Function arrayJoin (alias x) (children 1)
            ExpressionList (children 1)
             Function array (children 1)
              ExpressionList (children 4)
               Function array (children 1)
                ExpressionList
               Literal Array_[\'a\']
               Literal Array_[\'a\', \'b\']
               Function array (children 1)
                ExpressionList
