T-SQL query suggestion - sql

Question

CREATE TABLE #Emp
(
ID int,
Name varchar(100)
)
INSERT INTO #Emp
VALUES (1, 'AAA'), (2, 'BBB'), (3, 'CCC')
CREATE TABLE #Task
(
EmpID int,
TaskName varchar(100),
[Hours] int
)
INSERT INTO #Task
VALUES (1, 'Task-1', 2), (1, 'Task-2', 4), (1, 'Task-5', 3),
(2, 'Task-3', 2), (2, 'Task-4', 4), (2, 'Task-5', 3),
(3, 'Task-1', 2), (3, 'Task-1', 4), (3, 'Task-1', 6),
(3, 'Task-2', 3), (3, 'Task-6', 1)
#Emp
ID Name
--------
1 AAA
2 BBB
3 CCC
#Task:
EmpID TaskName Hours
-------------------------
1 Task-1 2
1 Task-2 4
1 Task-5 3
2 Task-3 2
2 Task-4 4
2 Task-5 8
3 Task-1 2
3 Task-1 4
3 Task-1 6
3 Task-2 3
3 Task-6 1
For each employee I need to get the sum of hours for (Task-1 and Task-2) and for Task-5
Something like below
Name PrepHours(Task-1 + Task-2) ReviewHours(Task-5)
-------------------------------------------------------
AAA 6 3
BBB 0 8
CCC 15 0
I tried the query shown here, but it fails with error column #Task.TaskName is invalid in the select list because it is not contained in either an aggregate function or the GROUP BY clause.
SELECT
Name, PrepHours, ReviewHours
FROM
#Emp AS E
JOIN
(SELECT
empid,
CASE
WHEN Taskname IN ('Task-1','Task-2')
THEN SUM(Hours)
ELSE 0
END AS 'PrepHours',
CASE
WHEN Taskname IN ('Task-5')
THEN SUM(Hours)
ELSE 0
END AS 'ReviewHours'
FROM
#Task
WHERE
Taskname IN ('Task-1', 'Task-2', 'Task-5')
GROUP BY
empid) AS t ON E.id = t.empid
ORDER BY
Name
So if I add the Taskname in the Group by it provides multiple rows for each. I need one row for each employee. Need help please.
Name PrepHours ReviewHours
-------------------------------
AAA 2 0
AAA 4 0
AAA 0 3
BBB 0 8
CCC 12 0
CCC 3 0

Answer 1

You can create your totals using a conditional case espression in a cross apply
select e.name, t.*
from #emp e
cross apply (
select
Sum(case when taskname in ('task-1','task-2') then hours else 0 end) PrepHours,
Sum(case when taskname ='Task-5' then hours else 0 end) ReviewHours
from #task t
where t.EmpId=e.Id
)t

Answer 2

You can make the original query work by moving the Sum outside the case statement:
SELECT [Name],
PrepHours,
ReviewHours
FROM #Emp AS E
JOIN (SELECT empid,
Sum( CASE
WHEN Taskname IN ( 'Task-1', 'Task-2' ) THEN [Hours]
ELSE 0
END) AS 'PrepHours',
sum(CASE
WHEN Taskname IN ( 'Task-5' ) THEN [Hours]
ELSE 0
END) AS 'ReviewHours'
FROM #Task
WHERE Taskname IN ( 'Task-1', 'Task-2', 'Task-5' )
GROUP BY empid) AS t
ON E.id = t.empid
ORDER BY Name