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Posted by Rory McKinley on 03/09/05 09:19
Jackson Linux wrote:
> Hi, all,
> I have three tables; 'cv', the main table, 'jobcat', a definition table
> and 'cvjobcats', an intersection table (for more detail see PS below).
>
> I'd like to join this all together to be able to make a headline
> consisting of the plain English description of the job category followed
> by all rows within cv which contain a reference to that job category
>
> I can follow this only to a point and that is where I ask for the List's
> help - does this even resemble the beginnings of what I want to
> accomplish? I've tried to comment as I go for my own sanity
>
>
> //Select columns from 'cv', whose 'category' references numbers
> //Select 'category' from 'jobcat' to translate the numbers to English
>
> "SELECT cv.cv_id,
> cv.category,
> dates,
> cv.job_title,
> cv.company,
> cv.job,
> jobcat.category
>
> FROM cv
> LEFT JOIN cvjobcats
> ON cvjobcats.cv=cv.cv_id //Let tables cv and jobcat understand each other.
>
> //This next bit I'm confused about
> LEFT JOIN jobcat
> ON jobcat.jobcat_id=cvjobcats.jobcat
> WHERE
> cvjobcats.jobcat='4'";
>
>
> Great. I'm now lost. Can anyone advise?
>
> Thanks in advance,
>
>
> PS:
> <far too much information>
> cv contains columns including an primary key ('cv_id') and a column
> called 'category' which refers to job categories by number.
>
> jobcat contains two fields: a primary key (jobcat_id) and a plain
> english description
>
> cvjobcat contains two key columns: 'cv_id' and 'jobcat_id'.
> </far too much information>
>
Hello Jackson
Are there any circumstances under which the cvjobcats table would have a
job category entry that does not appear in the jobcats table? IF not,
you really don't need to use the LEFT JOINS. Instead you coudl do
something like this:
SELECT cv.cv_id,cv.category,dates,cv.job_title,cv.company,cv.job,
jobcat.category
FROM cv, cvjobcats, jobcats
WHERE cvjobcats.cv=cv.cv_id AND cvjobcats_jobcat = 4 AND
jobcat.jobcat_id=cvjobcats.jobcat
Less technically impressive perhaps but easier to follow ;)
Regards
Rory
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