Explain EXPLAIN SYNTAX (children 1)
 SelectWithUnionQuery (children 1)
  ExpressionList (children 1)
   SelectQuery (children 3)
    ExpressionList (children 1)
     WithElement (children 1)
      Subquery (children 1)
       SelectWithUnionQuery (children 1)
        ExpressionList (children 1)
         SelectQuery (children 1)
          ExpressionList (children 1)
           Literal UInt64_1
    ExpressionList (children 1)
     Identifier lhs.d2
    TablesInSelectQuery (children 2)
     TablesInSelectQueryElement (children 1)
      TableExpression (children 1)
       Function view (alias lhs) (children 1)
        ExpressionList (children 1)
         SelectWithUnionQuery (children 1)
          ExpressionList (children 1)
           SelectQuery (children 2)
            ExpressionList (children 1)
             Identifier dummy (alias d2)
            TablesInSelectQuery (children 2)
             TablesInSelectQueryElement (children 1)
              TableExpression (children 1)
               TableIdentifier system.one
             TablesInSelectQueryElement (children 2)
              TableExpression (children 1)
               Subquery (alias a) (children 1)
                SelectWithUnionQuery (children 1)
                 ExpressionList (children 1)
                  SelectQuery (children 2)
                   ExpressionList (children 1)
                    Asterisk
                   TablesInSelectQuery (children 1)
                    TablesInSelectQueryElement (children 1)
                     TableExpression (children 1)
                      Function view (children 1)
                       ExpressionList (children 1)
                        SelectWithUnionQuery (children 1)
                         ExpressionList (children 1)
                          SelectQuery (children 2)
                           ExpressionList (children 1)
                            Identifier dummy (alias d2)
                           TablesInSelectQuery (children 1)
                            TablesInSelectQueryElement (children 1)
                             TableExpression (children 1)
                              TableIdentifier system.one
              TableJoin (children 1)
               Function equals (children 1)
                ExpressionList (children 2)
                 Identifier a.d2
                 Identifier d2
     TablesInSelectQueryElement (children 2)
      TableExpression (children 1)
       TableIdentifier rhs
      TableJoin (children 1)
       ExpressionList (children 1)
        Identifier d1
