SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 4)
   ExpressionList (children 3)
    Literal \'(backward, tail, B->A)\'
    Identifier id
    Function sequenceNextNode (alias next_node) (children 2)
     ExpressionList (children 5)
      Identifier dt
      Identifier action
      Literal UInt64_1
      Function equals (children 1)
       ExpressionList (children 2)
        Identifier action
        Literal \'B\'
      Function equals (children 1)
       ExpressionList (children 2)
        Identifier action
        Literal \'A\'
     ExpressionList (children 2)
      Literal \'backward\'
      Literal \'tail\'
   TablesInSelectQuery (children 1)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      TableIdentifier test_sequenceNextNode_Nullable
   ExpressionList (children 1)
    Identifier id
   ExpressionList (children 1)
    OrderByElement (children 1)
     Identifier id
