SQL Query If Condition for specific text within two rows - sql

Question

I need to write a query, but I'm not exactly sure how to write it. I need to grab all the EmployeeIds based off the status. If it is completed and pending, completed takes precedence. However, if there is only pending and not completed I'll take pending, else don't take any of the rows for that employee. I just need one item per EmployeeId. Technically I would also need to grab the earliest date but I think I would know how to write that part.
RowNumber Status EmployeeId Produce Date
-------------------------------------------------------
1 New 1 Apples 1/1/18
2 Pending 1 BlueBerry 1/2/18
3 New 1 Oranges 1/3/18
4 Pending 2 Bananas 1/1/18
5 New 2 Grapes 1/2/18
6 Complete 2 Limes 1/3/18
So in this example I need the following below
RowNumber Status EmployeeId Produce Date
--------------------------------------------------------
2 Pending 1 BlueBerry 1/2/18
6 Complete 2 Limes 1/3/18
The hardest part for me is trying to figure out how to compare strings. Basically (semi pseudo-code)
Select top 1
t.EmployeeId, t.Produce, t.Date, stat.Status
(Case
If t.Status = 'Complete'
Select 'Complete'
If t.Status = 'Pending'
Select 'Pending'
Else
Dont Add this row ) stat
From
Table t
Where
t.Status = 'Complete' or t.Status = 'Pending'
Order by
t.Date

Answer 1

There's at least two different approaches coming to my mind :
SELECT DISTINCT EmployeeId
FROM Table
WHERE Status = "Complete"
UNION
SELECT DISTINCT t1.EmployeeId
FROM Table t1
LEFT OUTER JOIN Table t2
ON t2.EmployeeId = t1.EmployeeId
AND t2.Status = "Complete"
WHERE t1.Status = "Pending"
AND t2.Status IS NULL
… or using coalesce() if your database engine supports it:
SELECT DISTINCT pend.EmployeeId,
coalesce(comp.Status,pend.Status),
coalesce(comp.RowNumber,pend.RowNumber)
FROM MyTable pend
LEFT OUTER JOIN MyTable comp
ON comp.EmployeeId = pend.EmployeeId
AND comp.Status = 'Complete'
WHERE pend.Status IN ('Complete','Pending');

Answer 2

Is this what you want using row_number() :
select top (1) with ties *
from table t
where Status in ('Completed', 'Pending')
order by row_number() over (partition by EmployeeId
order by (case Status when 'Completed'
then 0
when 'Pending'
then 1
end)
);

Answer 3

You could do this with a UNION ALL coupled with a WHERE NOT EXISTS:
SELECT t1.*
FROM [Table] t1
WHERE [Status] = 'Completed'
UNION ALL
SELECT t2.*
FROM [Table] t2
WHERE [Status] = 'Pending'
AND NOT EXISTS (
SELECT 1
FROM [Table]
WHERE EmployeeId = t2.EmployeeId
AND [Status] = [Completed]
);

Answer 4

You could calculate a ROW_NUMBER that uses a CASE WHEN.
And then filter on that.
For example:
SELECT RowNumber, [Status], EmployeeId, Produce, [Date]
FROM
(
SELECT
RowNumber, [Status], EmployeeId, Produce, [Date],
ROW_NUMBER() OVER (
PARTITION BY EmployeeId
ORDER BY [Date] DESC,
CASE [Status] WHEN 'Complete' THEN 1 WHEN 'Pending' THEN 2 ELSE 9 END
) AS RN
FROM [YourTable] t
WHERE [Status] IN ('Complete','Pending')
) q
WHERE RN = 1
ORDER BY EmployeeId