Re: time stamp specific to columns
On 2015/04/08 11:42, Andrew Wallace wrote: I think you'd have to do that with a trigger. Yes, one can do that with a trigger, but it is a real pain. MySQL now allows (new.a,new.b,new.c,new.d) <> (old.a,old.b,old.c,old.d) but one needs to beware of NULL. Maybe it is better to split off the timestampy part to another table, and join them when needed. On 4/8/15 6:36 AM, Martin Mueller wrote: I understand how a timestamp column automatically changes when there is a change in a data row. Is it possible to limit the update to changes in particular columns? I have a table where I care about changes in any of four different columns, but I don¹t care about changes in other columns or added columns. Is there a command that says ³update the time stamp if and only if there is a change in columns a, b,c, or d" -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe:http://lists.mysql.com/mysql
Re: time stamp specific to columns
A trigger is far simpler than remodelling your data and adding extra queries. They are nothing to be afraid of. On Thu, Apr 9, 2015 at 10:46 AM, wrote: > On 2015/04/08 11:42, Andrew Wallace wrote: > >> I think you'd have to do that with a trigger. >> > > Yes, one can do that with a trigger, but it is a real pain. MySQL now > allows > (new.a,new.b,new.c,new.d) <> (old.a,old.b,old.c,old.d) > but one needs to beware of NULL. Maybe it is better to split off the > timestampy part to another table, and join them when needed. > > > On 4/8/15 6:36 AM, Martin Mueller wrote: >> >>> I understand how a timestamp column automatically changes when there is a >>> change in a data row. Is it possible to limit the update to changes in >>> particular columns? I have a table where I care about changes in any of >>> four different columns, but I don¹t care about changes in other >>> columns or >>> added columns. >>> >>> Is there a command that says ³update the time stamp if and only if there >>> is a change in columns a, b,c, or d" >>> >> > -- > MySQL General Mailing List > For list archives: http://lists.mysql.com/mysql > To unsubscribe:http://lists.mysql.com/mysql > > -- - michael dykman - mdyk...@gmail.com May the Source be with you.
Re: store search result as new table in memory
On Tue, 7 Apr 2015, shawn l.green wrote: Temporary tables are going to become your very good friends. yes I do use temporary tables a lot The advantage to using temporary tables is that they can have indexes on them. You can create the indexes when you create the table or you can ALTER the table later to add them. if they are big, using proper indices is a must to get quick responses. -- Lucio Chiappetti - INAF/IASF - via Bassini 15 - I-20133 Milano (Italy) For more info : http://www.iasf-milano.inaf.it/~lucio/personal.html Do not like Firefox >=29 ? Get Pale Moon ! http://www.palemoon.org -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe:http://lists.mysql.com/mysql
