Conditional Count on a field
If I had a table like this:
jobId, jobName, Priority
Whereby Priority can be an integer between 1 to 5.
Since I would need this query for generating a chart on report, I would need to display the jobid, jobname and 5 fields called Priority1, Priority2, Priority3, Priority4. Priority5.
Priority1 should count the amount of rows where priority field has the value of 1.
Priority2 should count the amount of rows where priority field has the value of 2.
Priority3 should count the amount of rows where priority field has the value of 3.
etc
How would I do that in a quick and performant manner?
I think you may be after
select
jobID, JobName,
sum(case when Priority = 1 then 1 else 0 end) as priority1,
sum(case when Priority = 2 then 1 else 0 end) as priority2,
sum(case when Priority = 3 then 1 else 0 end) as priority3,
sum(case when Priority = 4 then 1 else 0 end) as priority4,
sum(case when Priority = 5 then 1 else 0 end) as priority5
from
Jobs
group by
jobID, JobName
However I am uncertain if you need to the jobID and JobName in your results if so remove them and remove the group by,
Using COUNT instead of SUM removes the requirement for an ELSE statement:
SELECT jobId, jobName,
COUNT(CASE WHEN Priority=1 THEN 1 END) AS Priority1,
COUNT(CASE WHEN Priority=2 THEN 1 END) AS Priority2,
COUNT(CASE WHEN Priority=3 THEN 1 END) AS Priority3,
COUNT(CASE WHEN Priority=4 THEN 1 END) AS Priority4,
COUNT(CASE WHEN Priority=5 THEN 1 END) AS Priority5
FROM TableName
GROUP BY jobId, jobName
IIF
is not a standard SQL construct, but if it's supported by your database, you can achieve a more elegant statement producing the same result:
SELECT JobId, JobName,
COUNT(IIF (Priority=1, 1, NULL)) AS Priority1,
COUNT(IIF (Priority=2, 1, NULL)) AS Priority2,
COUNT(IIF (Priority=3, 1, NULL)) AS Priority3,
COUNT(IIF (Priority=4, 1, NULL)) AS Priority4,
COUNT(IIF (Priority=5, 1, NULL)) AS Priority5
FROM TableName
GROUP BY JobId, JobName