Question

I have a request that return bad result and I can’t fix it,the calculation is wrong ,

My query:

select TIMEDIFF(a.CREATED,b.CREATED) 
from
(
  select changegroup.CREATED 
  from changegroup,changeitem,project,jiraissue
  where  changegroup.id=changeitem.groupid
  and field='Group'
  and oldString='Triage' 
  and jiraissue.id=changegroup.issueid 
  and project.id=jiraissue.project 
  and project.pname='Test'
  and jiraissue.CREATED between '2011-08-11 14:01:00' and  '2011-08-11 14:11:00'  
) a,
(
  select jiraissue.CREATED 
  from jiraissue ,changegroup,project
  where jiraissue.id=changegroup.issueid 
  and project.id=jiraissue.project 
  and project.pname='Test'
  and jiraissue.CREATED between '2011-08-11 14:01:00' and '2011-08-11 14:11:00' 
) b;

the result of the subquery1:

the result of the subquery2:

The Result of the query:

The Result wanted :

The relation between tables

thank you

Answer 1

First of all I’d rewrite your query as follows, just to clearly show the connections between the tables in the query:

select TIMEDIFF(a.created,b.created) 
from
    (
        select g.created
        from   changegroup g
        join   changeitem ci on (ci.groupId = g.id)
        join   jiraissue ji on (ji.id = g.id)
        join   project p on (p.id = ji.project)
        where  ci.field = 'Group'
               and ci.oldString = 'Triage' 
               and p.pname = 'Test'
               and ji.created between '2011-08-11 14:01:00' and  '2011-08-11 14:11:00'
    ) a
join    (
        select ji.created
        from   jiraissue ji
        join   changegroup g on (g.issueid = ji.id)
        join   project p on (p.id = ji.project)
        where  p.pname = 'Test'
          and  ji.created between '2011-08-11 14:01:00' and '2011-08-11 14:11:00' 
    ) b;

I think you are missing the link between two subqueries. It really depends on what you are trying to accomplish. If I understood you well, and you just want to calculate the time difference between jira issue creation date and the creation date the issue belongs to, following query should do the trick (more less, based on your query):

select TIMEDIFF(a.created,b.created) 
from
    (
        select g.created, g.id as groupid
        from   changegroup g
        join   changeitem ci on (ci.groupId = g.id)
        join   jiraissue ji on (ji.id = g.id)
        join   project p on (p.id = ji.project)
        where  ci.field = 'Group'
      and  ci.oldString = 'Triage' 
      and  p.pname = 'Test'
      and  ji.created between '2011-08-11 14:01:00' and  '2011-08-11 14:11:00'
    ) a
left join   (
        select ji.created, g.id as groupid
        from   jiraissue ji
        join   changegroup g on (g.issueid = ji.id)
        join   project p on (p.id = ji.project)
        where  p.pname = 'Test'
          and  ji.created between '2011-08-11 14:01:00' and '2011-08-11 14:11:00' 
    ) b ON (a.groupid = b.groupid)

Please specify in detail what are you trying to accomplish and maybe I could help more.