php - Mysql: Gap detection query not detecting gaps -

-

it seems though gap detection picking whatever set timedifference , doing every interval based on that.

so here's explanation of data structure , i'm after:

i have database that's set this:

(schema name) historical      -cid      int uq ai nn       -id       int pk      -location varchar(255)      -status   varchar(255)      -time     datetime

my data comes in looking (example 5 rows selected id)

 433275 | 97  | mylocation | ok | 2013-08-20 13:05:54  433275 | 97  | mylocation | ok | 2013-08-20 13:00:54  433275 | 97  | mylocation | ok | 2013-08-20 12:25:54  433275 | 97  | mylocation | ok | 2013-08-20 12:20:54  433275 | 97  | mylocation | ok | 2013-08-20 12:15:54

in case above you'll notice i'm missing data 12:25:54 -> 13:00 id 97. trying write report tell me the: start of downtime, duration of downtime, , end of downtime (which i've been handling in php adding timediff time)

here's code (php -> mysql) (non-working) stands now:

        select *from (             select             y.*,             timestampdiff(minute, @prevdt, `time`) timedifference,             @prevdt := `time`             ddhistorical y,             (select @prevdt:=(select min(`time`) ddhistorical)) vars             id  = '". mysql_real_escape_string($id)."'             having timedifference > 16           ) s           order time desc           limit 25";

you need 2 levels of subquery:

select * (     select  y.*,             timestampdiff(minute, @prevdt, `time`) timedifference,             @prevdt := `time`             (select *                   ddhistorical                   id = '97'                   order `time`) y,                  (select @prevdt:=(select min(`time`) ddhistorical)) vars) z timedifference > 16 limit 25

i'm not sure why outermost level needed. tried without (i.e. starting select y.*) , using having timedifference > 16. reason, reported single row timedifference = 45. if removed having clause, showed rows, gap reported 35 minutes. usually, there's no difference between 

select ... having <cond>

and

select * (select ...) <cond>

i'm not sure why query violates rule -- suspect has user-variables.

edit:

i think i've figured out why didn't work having. mysql apparently evaluating condition calculates timedifference column each row, , discarding row. when timedifference <= 16, doesn't bother calculating rest of columns in select clause, never @prevdt := time. until gets past condition, it's comparing min(time).

moving timedifference check outer query forces calculate differences before filtering.

sqlfiddle


Comments

Post a Comment

Popular posts from this blog

java - Run a .jar on Heroku -

-
i trying run .jar file on heroku, , can't find instructions anywhere on how this. have read wants me compile uploading heroku. possible, , if is, how this? if helps, trying run minecraft craftbukkit server, , don't have pom.xml file yet. you didn't provide details i'll try give , people reaches question way it. first of all, create heroku account , create heroku application (assumed have done that). second, need generate application jar , upload heroku. so, open terminal , install heroku cli (assuming unix terminal): $ sudo npm install -g heroku-cli you need have npm , nodejs installed, can check link: https://www.digitalocean.com/community/tutorials/how-to-install-node-js-on-ubuntu-16-04 once done that, can use npm update node version acceptable heroku-cli: $ sudo npm install -g n $ sudo n 7.10.0 and run: $ sudo npm install -g heroku-cli in order deploy jars, need install deploy plugin: $ sudo heroku plugins:install heroku-cli-deploy ...
Read more

java - Jtable duplicate Rows -

-
Image
when add new rows in jtable duplicate rows many times this method update jtable public final void tableaucomande(){ ((defaulttablemodel)tabcommande.getmodel()).getdatavector().clear(); session s=hibernateutil.getsessionfactory().opensession(); criteria cr1= s.createcriteria(commande.class); list <commande> lcs=cr1.list() ; criteria cr2= s.createcriteria(lignecommande.class); list <lignecommande> lck=cr2.list() ; if(lcs.size()!=0 && lck.size()!=0) { (commande lc:lcs) { for(lignecommande lig:lck){ ((defaulttablemodel)tabcommande.getmodel()).addrow(new object[]{ lc.getid_cmd(),lc.getnumcmd(),lc.getdate_cmd(),lc.getclient().getnomprenom(), lig.getproduit().getlib_prd(),lig.getquantite(),lig.getproduit().getid_prd() }); } } // tabcommande.setrowselectioninterval(tabcommande.getrowcount()-1,tabcommande.getrowcount()-1); } } this code add add data rows displaye...
Read more

validation - How to pass paramaters like unix into windows batch file -

-
i need pass various parameters .cmd file unix format file.cmd -configuration=value -source=value -flag but, try this: startlocal @echo off cls setlocal set cmdline=%* set configuration= set source= set badargs= set validation= goto main :splitargs echo splitargs(%*) if "%*" neq "" ( /f "tokens=1,2,* delims== " %%i in ("%*") call :assignkeyvalue %%i %%j & call :splitargs %%k ) goto :eof :assignkeyvalue echo assignkeyvalue(%1, %2) if /i %1==-configuration ( set configuration=%2 ) else if /i %1==-source ( set source=%2 ) else ( rem append unrecognised [key,value] badargs echo unknown key %1 set badargs=%badargs%[%1, %2] ) goto :eof :validate echo validating set validation=fail if defined configuration ( echo -configuration ok if defined source ( echo -source ok if not defined badargs ( set validation=success ) ) ) goto :eof :main cl...
Read more