2005/9/17, Miguel Cardenas <[EMAIL PROTECTED]>: > > In the last episode (Sep 17), Miguel Cardenas said: > > > I have a technical doubt, very simple but not mentioned in the manual... > > > > > > What happens if I call mysql_free_result() after performing a query > > > but without doing mysql_fetch_row() ??? > > > > > > It may sound strange, but just need to know if a data row exists more > > > than the data itself... > > > > A faster way would be to run a "SELECT count(*) WHERE ..." query, and > > check the result. Since you are not selecting any data, mysql is more > > likely to be able to use index lookups to speed the query up. > > Well, in fact don't want to check if there is data already inserted on the > table to make condition TRUE, what I want is to do this: > > SELECT id,data FROM table WHERE id=XXX > > but, just want to check if it the search found something and then free the > resources, not to retrieve the data... in short words: > > 1. search rows which id=XXX > 2. if mysql_num_rows() > 0 then CONDITION=TRUE else CONDITION=FALSE > 3. mysql_free_result() > > WHY? well, this operation will be repeated over 100,000 times and only need to > know if the specified data exists, the difference between just know and > retrieve 1 time and 100,000 times surely would be significative if I try > > 1. search rows which id=XXX > 2. if mysql_fetch_row() then CONDITION=TRUE else CONDITION=FALSE > 3. mysql_free_result() > > Specifically, my doubt is, what happen if I call mysql_free_result() if I > don't call mysql_fetch_row() before, or if not all rows are read before > calling it...
http://dev.mysql.com/doc/mysql/en/mysql-free-result.html it does not says : you have to retrieve all rows before freing it. So you should be able to free the result. Otherwise it's a bug or undocumented behaviour. But why don't you use the Count(*) solution ?? that's exactly what you need IMHO. -- Pooly Webzine Rock : http://www.w-fenec.org/ -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
