How to Select * Where Everything is Distinct Except One Field - sql

Question

I'm trying to pull 6 records using the code below but there are some cases where the information is updated and therefore it is pulling duplicate records.
My code:
SELECT column2, count(*) as 'Count'
FROM ServiceTable p
join HIERARCHY h
on p.LOCATION_CODE = h.LOCATION
where Report_date between '2017-04-01' and '2017-04-30'
and Column1 = 'Issue '
and LOCATION = '8789'
and
( record_code = 'INCIDENT' or
(
SUBMIT_METHOD = 'Web' and
not exists
(
select *
from ServiceTable p2
where p2.record_code = 'INCIDENT'
and p2.incident_id = p.incident_id
)
)
)
The problem is that instead of the six records it is pulling eight. I would just use distinct * but the file_date is different on the duplicate entries:
FILE_DATE Incident_ID Column1 Column2
4/4/17 123 Issue Service - Red
4/4/17 123 Issue Service - Blue
4/5/17 123 Issue Service - Red
4/5/17 123 Issue Service - Blue
The desired output is:
COLUMN2 COUNT
Service - Red 1
Service - Blue 1
Any help would be greatly appreciated! If you need any other info just let me know.

Answer 1

If you turn your original select statement without the aggregation function into a subquery, you can distinct that on your values that are not the changing date, then select a COUNT from there. Don't forget your GROUP BY clause at the end.
SELECT Column2, COUNT(Incident_ID) AS Service_Count
FROM (SELECT DISTINCT Incident_ID, Column1, Column2
FROM ServiceTable p
JOIN HIERARCHY h ON p.LOCATION_CODE = h.LOCATION
WHERE Report_date BETWEEN '2017-04-01' AND '2017-04-30'
AND Column1 = 'Issue '
AND LOCATION = '8789'
AND
( record_code = 'INCIDENT' or
(
SUBMIT_METHOD = 'Web' and
NOT EXISTS
(
SELECT *
FROM ServiceTable p2
WHERE p2.record_code = 'INCIDENT'
AND p2.incident_id = p.incident_id)
)
)
)
GROUP BY Column2
Also, if you are joining tables it is a good practice to fully qualify the field you are selecting. Example: p.Column2, p.Incident_ID, h.LOCATION. That way, even your distinct fields are easier to follow where they came from and how they relate.
Finally, don't forget that COUNT is a reserved word. I modified your alias accordingly.

Answer 2

If you are using an aggregation function (count), you should use group by for the column not in the aggregation function:
SELECT column2, count(*) as 'Count'
FROM ServiceTable p
join HIERARCHY h
on p.LOCATION_CODE = h.LOCATION
where Report_date between '2017-04-01' and '2017-04-30'
and Column1 = 'Issue '
and LOCATION = '8789'
and
( record_code = 'INCIDENT' or
(
SUBMIT_METHOD = 'Web' and
not exists
(
select *
from ServiceTable p2
where p2.record_code = 'INCIDENT'
and p2.incident_id = p.incident_id
)
)
)
group by column2