Hi Vikram, NULL is a special data type and requires special procedures.
Try this: > mysql> delete from clients where cid = (select clients.cid from clients > left join branches using (cid) WHERE ISNULL(bid); Please make NO SPACE betwen ISNULL and (bid) as otherwise wit will give you an syntax error. Hope that ends the problems you had. Best regards Nils Valentin Tokyo/Japan 2003年 7月 25日 金曜日 12:58、Vikram Vaswani さんは書きました: > Hi all, > > I have the following two tables: > > mysql> SELECT * FROM clients; > +-----+-----------------------------+ > > | cid | cname | > > +-----+-----------------------------+ > > | 101 | JV Real Estate | > | 102 | ABC Talent Agency | > | 103 | DMW Trading | > | 104 | Rabbit Foods Inc | > | 110 | Sharp Eyes Detective Agency | > > +-----+-----------------------------+ > 5 rows in set (0.00 sec) > > mysql> SELECT * FROM branches; > +------+-----+--------------------------------+------+ > > | bid | cid | bdesc | bloc | > > +------+-----+--------------------------------+------+ > > | 1011 | 101 | Corporate HQ | CA | > | 1012 | 101 | Accounting Department | NY | > | 1013 | 101 | Customer Grievances Department | KA | > | 1041 | 104 | Branch Office (East) | MA | > | 1042 | 104 | Branch Office (West) | CA | > | 1101 | 110 | Head Office | CA | > | 1031 | 103 | N Region HO | ME | > | 1032 | 103 | NE Region HO | CT | > | 1033 | 103 | NW Region HO | NY | > > +------+-----+--------------------------------+------+ > 9 rows in set (0.01 sec) > > I need to delete all clients with no branches. I need to use a subquery to > do this. Given these constraints, I came up with the following: > > mysql> delete from clients where cid = (select clients.cid from clients > left join branches using (cid) WHERE bid is null); > > MySQL says: > > ERROR 1093: You can't specify target table 'clients' for update in FROM > clause > > Does any one know why I am getting this error (MySQL 4.1)? Can you help me > rewrite this operation *using a subquery only*? > > TIA, > > Vikram -- --- Valentin Nils Internet Technology E-Mail: [EMAIL PROTECTED] URL: http://www.knowd.co.jp Personal URL: http://www.knowd.co.jp/staff/nils -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
