SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 3)
   ExpressionList (children 2)
    Identifier name
    Identifier c
   TablesInSelectQuery (children 2)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      TableIdentifier users
    TablesInSelectQueryElement (children 2)
     TableExpression (children 1)
      Subquery (alias messages) (children 1)
       SelectWithUnionQuery (children 1)
        ExpressionList (children 1)
         SelectQuery (children 3)
          ExpressionList (children 2)
           Identifier user_id
           Function count (alias c) (children 1)
            ExpressionList
          TablesInSelectQuery (children 1)
           TablesInSelectQueryElement (children 1)
            TableExpression (children 1)
             TableIdentifier messages
          ExpressionList (children 1)
           Identifier user_id
     TableJoin (children 1)
      Function equals (children 1)
       ExpressionList (children 2)
        Identifier messages.user_id
        Identifier users.id
   ExpressionList (children 2)
    OrderByElement (children 1)
     Identifier user_id
    OrderByElement (children 1)
     Identifier c
