Thanks. I used SELECT Start_time, End_time FROM Table WHERE Start_time - DATE_SUB( NOW(), INTERVAL 4 HOUR ) >=0
It works. -----Original Message----- From: Wesley Furgiuele [mailto:[EMAIL PROTECTED] Sent: Wednesday, August 18, 2004 3:11 PM To: Viswanatha Rao Cc: [EMAIL PROTECTED] Subject: Re: select rows by compare on datetime column - more on time decrement What version of MySQL are you using? You have different options. http://dev.mysql.com/doc/mysql/en/Date_and_time_functions.html Look at DATE_SUB() and SUBDATE()/SUBTIME(). The time part of the query would look something like DATE_FORMAT( DATE_SUB( NOW(), INTERVAL 4 HOUR ), '%H:%i:%s' ), or something like that. Or, this might be better handled in Perl, just using Perl to control the time value supplied in the query -- I'm not sure about your "and so on". I wouldn't know how to handle a series of t1, t2, t3, t4, ..., tn without use of a scripting/programming language. Wes On Aug 18, 2004, at 3:44 PM, Viswanatha Rao wrote: > I have to select mysql rows based on the following condition. > Time t1 = (current time - 4 hours); > Time t2 = (current time - 8 hours); > In my case, I want to select all those rows that have start times > (1) between current time and t1 > (2) between time t1 and t2 > ... and so on > > So I have to somehow subtract hours from the current time to get t1, > t2, > and so on. In some other cases, I may have to subtract specific number > of minutes. > > So my question is how do I selectively subtract hours or minutes from > current time in mysql. > > I need these values to plot a chart. Please let me know? > > > -----Original Message----- > From: Wesley Furgiuele [mailto:[EMAIL PROTECTED] > Sent: Wednesday, August 18, 2004 11:36 AM > To: Viswanatha Rao > Cc: [EMAIL PROTECTED] List > Subject: Re: select rows by compare on datetime column > > Vishwa: > > Sorry -- I used a specific time value as an example, but since you were > asking about current time, you would use CURTIME(): > > SELECT columns FROM table WHERE DATE_FORMAT( start_time, '%H:%i:%s' ) >> = CURTIME() AND DATE_FORMAT( end_time, '%H:%i:%s' ) <= CURTIME(); > > Wes > > > On Aug 18, 2004, at 12:24 PM, Wesley Furgiuele wrote: > >> Does the date matter, or only the time? >> >> If date matters (you want to find all records between 2004-06-01 >> 10:00:00 AND 2004-06-03 18:00:00): >> SELECT columns FROM table WHERE start_time >= '2004-06-01 10:00:00' >> AND end_time <= '2004-06-03 18:00:00' >> >> >> If only time matters( you want to find all records between 10:00:00 >> AND 18:00:00 on any day): >> --> If you're using version 4.1.1 or greater: >> SELECT columns FROM table WHERE TIME( start_time ) >= '10:00:00' AND >> TIME( end_time ) >= '18:00:00' >> --> Otherwise: >> SELECT columns FROM table WHERE DATE_FORMAT( start_time, '%H:%i:%s' ) >>> = '10:00:00' AND DATE_FORMAT( end_time, '%H:%i:%s' ) <= '18:00:00' >> >> Wes >> >> >> On Aug 18, 2004, at 11:39 AM, Viswanatha Rao wrote: >> >>> I have two columns in a table: start_time and end_time. Both are of >>> types DATETIME >>> When I select rows from table, I want to select only those rows where >>> the current time falls between start_time and end_time >>> >>> Can someone help with the SELECT syntax for this? >>> >>> Best Regards >>> Vishwa Rao >>> >>> >>> >> >> >> -- >> MySQL General Mailing List >> For list archives: http://lists.mysql.com/mysql >> To unsubscribe: >> http://lists.mysql.com/[EMAIL PROTECTED] >> >> > > -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED] -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
