Using a view to join two tables

Question

Thank you in advance for any advice you can lend.
I am using this code in my MySQL db to create a view.
select
    job.id as job_id,
    umr_cost_calculation.plant_name,
    max(umr_cost_calculation.id) as max_id
from
    job,
    umr_cost_calculation
where
    job.id = umr_cost_calculation.job_id
group by job.id , umr_cost_calculation.plant_name
I did this so I can join two tables and pull in the most current cost data for a specific plant. The report will, at times, show the wrong (older) data. I can re-run the report, filter to just the one job and see again the wrong data. When I add the max_id to the report, it display the id and updates the report with the correct data. It appears that the view was stale and by adding the ID to the report this fixed the issue.
1) Is this the best way to make this join? I don't see how Crystal supports a subquery to make a join (this is why I used the view).
2) If I leave the max_id on the report, will this force the view to always update?

Answer 1

Try:
Select
D1.EmpLoginID,
Count(D1.ID),
Count(D1.AlarmCode),
D1.EmpName,
D1.EmpAddress,
D2.Db2Count
FROM DB1.Data D1
LEFT JOIN (SELECT
empLoginID, Count(*) as Db2Count
FROM DB2.ALL_Database
WHERE site = 'Atlanta'
GROUP BY empLoginID
) D2
ON D1.EmpLoginID = D2.EmpLoginID
GROUP BY D1.empLoginID, D1.EmpName, D2.EmpAddress, D2.Db2Count
Order BY D1.empLoginID ASC
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