SQL to Select lowest value, group by, other field - sql

Question

I'm having a problem writing a query that gives me the other fields after finding the min value of another column. I've tried this:
Select WorkOrder, min(Job), Details
From Jobs
Group by WorkOrder
But it doesn't work.
This gives me a list of the lowest Job number by WorkOrder:
Select WorkOrder, min(Job)
From Jobs
Group by WorkOrder
I want Details of the line item with the lowest Job number. What am I doing wrong?

Answer 1

You may try this query
Select WorkOrder, min(Job), Details
From Jobs
Group by WorkOrder, Details

Answer 2

When you use a GROUP BY clause, everything in your select statement has to either be an aggregate function (like min, max, ect) or has to be included in your GROUP BY clause. Details is not included in your GROUP BY clause, and so the statement won't compile. If you include Details in your GROUP BY clause you will get the min(job) of each combination of WorkOrder and Details, which is probably not what you want.
There are a few ways you can go about solving this problem. IMO the easiest would be to select your min(job) and Workorder, and then to join that result back into the jobs table and select details. To do this your jobs table must have a unique primary key.
SELECT
minWorkOrder.WorkOrder
minWorkOrder.MinJob
Jobs.Details
FROM
(Select Key, WorkOrder, min(Job) as MinJob
From Jobs
Group by Key, WorkOrder) AS minWorkOrder
INNER JOIN Jobs
ON Jobs.Key = minWorkOrder.Key
If your table does not have a unique key, then things get a littler trickier. In the scope of this query, it is probably a safe assumption that every combination of min(Job) and WorkOrder is unique. You can join on both of these fields and yous should get the right answer.
SELECT
minWorkOrder.WorkOrder
minWorkOrder.MinJob
Jobs.Details
FROM
(Select WorkOrder, min(Job) as MinJob
From Jobs
Group by WorkOrder) AS minWorkOrder
INNER JOIN Jobs
ON Jobs.Job = minWorkOrder.MinJob AND Jobs.WorkOrder = minWorkOrder.WorkOrder

Answer 3

you should add min() in your condition like this
Select * From Jobs Where Job in
(Select min_job From (Select WorkOrder ,min(Job) as min_job From Jobs
Group by WorkOrder)
)

Answer 4

You should try this:
SELECT WorkOrder, Details
from Jobs
where Job IN (SELECt min(Job), WorkOrder from Jobs GROUP BY WorkOrder);

Answer 5

I worked with an engineer in my department who provided this working answer:
Select A.WorkOrder, A.Job, A.Details
From(Select WorkOrder, Job, Details, Row_Number()
over( Partition by WorkOrder Order by Job ASC) as Num
From Jobs)A
where A.Num = 1

Answer 6

with cte as
(
select workorder,Job, Details, rank() over (partition by workorder order by job asc) as rnk
from
Jobs
)
select workorder,Job, Details from cte
where rnk = 1
Here we are ranking values in column Job in ascending order, for each workorder. Last WHERE clause rnk = 1 fetches only the Jobs with minimum value for each workorder. In case a workorder has more than 1 jobs with same value, RANK() will assign same rank to them . Hence, if a workorder has more than 1 jobs with minimum value ,this will return all of them.