Thanks a lot. I got the answer. "Impossible where in explian" comes when the query doesn't make any sense to the mysql optimizer.
Please visit the link below for more details. http://books.google.co.in/books?id=sgMvu2uZXlsC&pg=PA94&lpg=PA94&dq=impossible+where+noticed+after&source=web&ots=fsQxHni1Ey&sig=k449ikPwIi4O-11whdD9MuNdbhM&hl=en&sa=X&oi=book_result&resnum=5&ct=result#PPA94,M1 On Tue, Sep 2, 2008 at 6:18 AM, Martin Gainty <[EMAIL PROTECTED]> wrote: > The key_len column indicates the length of the key that MySQL decided to > use. The length is NULL if the key column says NULL. Note that the value > of key_len allows you to determine how many parts of a multiple-part key > MySQL will actually use. > > i do not know the definition of parameter 'ken_len' > > Martin > ______________________________________________ > Disclaimer and confidentiality note > Everything in this e-mail and any attachments relates to the official > business of Sender. This transmission is of a confidential nature and Sender > does not endorse distribution to any party other than intended recipient. > Sender does not necessarily endorse content contained within this > transmission. > > > > Date: Tue, 2 Sep 2008 02:05:00 +0530 > > From: [EMAIL PROTECTED] > > To: [EMAIL PROTECTED] > > Subject: Re: Impossible WHERE in explain > > CC: mysql@lists.mysql.com > > > > > I have already tried. It's not working. > > > > On Tue, Sep 2, 2008 at 1:55 AM, Brent Baisley <[EMAIL PROTECTED]> > wrote: > > > > > It might be because you you are comparing user_id to a string, when the > > > field type is a decimal. Drop the quotes around the user_id search > value and > > > see if that works. > > > > > > Brent Baisley > > > > > > > > > On Sep 1, 2008, at 3:59 PM, Krishna Chandra Prajapati wrote: > > > > > > Hi, > > >> > > >> In the query below explain gives 'Impossible WHERE noticed after'. > what > > >> does > > >> this mean. > > >> > > >> CREATE TABLE `user_cookie` ( > > >> `user_id` decimal(22,0) NOT NULL default '0', > > >> `param` varchar(128) NOT NULL default '', > > >> `value` varchar(128) default NULL, > > >> PRIMARY KEY (`user_id`,`param`), > > >> CONSTRAINT `fk_user_cookie` FOREIGN KEY (`user_id`) REFERENCES > > >> `user_info` (`user_id`) ON DELETE NO ACTION ON UPDATE NO ACTION > > >> ) ENGINE=InnoDB DEFAULT CHARSET=latin1 > > >> > > >> SELECT VALUE FROM user_cookie WHERE USER_ID = '10538485' AND PARAM = > > >> 'TIMEOUT' table |type |possible_keys |key | ken_len|ref | rows| 1 > > >> |SIMPLE | | | | | |Impossible WHERE noticed afte > > >> -- > > >> Krishna Chandra Prajapati > > >> > > > > > > > > > > > > -- > > Krishna Chandra Prajapati > > > ------------------------------ > Be the filmmaker you always wanted to be—learn how to burn a DVD with > Windows(R). Make your smash > hit<http://clk.atdmt.com/MRT/go/108588797/direct/01/> > -- Krishna Chandra Prajapati MySQL DBA, Ed Ventures e-Learning Pvt.Ltd. 1-8-303/48/15, Sindhi Colony P.G.Road, Secunderabad. Pin Code: 500003 Office Number: 040-66489771 Mob: 9912924044 URL: ed-ventures-online.com Email-id: [EMAIL PROTECTED]
