Stored procedure that returns a table from 2 combined - sql

Question

I am trying to write a stored procedure which returns a result combining 2 table variables which looks something like this.
Name | LastName | course | course | course | course <- Columns
Name | LastName | DVA123 | DVA222 | nothing | nothing <- Row1
Pete Steven 200 <- Row2
Steve Lastname 50 <- Row3
From these 3 tables
Table Staff:
Name | LastName | SSN |
Steve Lastname 234
Pete Steven 132
Table Course Instance:
Course | Year | Period |
DVA123 2013 1
DVA222 2014 2
Table Attended by:
Course | SSN | Year | Period | Hours |
DVA123 234 2013 1 200
DVA222 132 2014 2 50
I am taking #year as a parameter that will decide what year in the course will be displayed in the result.
ALTER proc [dbo].[test4]
#year int
as
begin
-- I then declare the 2 tables which I will then store the values from the tables
DECLARE #Table1 TABLE(
Firstname varchar(30) NOT NULL,
Lastname varchar(30) NOT NULL
);
DECLARE #Table2 TABLE(
Course varchar(30) NULL
);
Declare #variable varchar(max) -- variable for saving the cursor value and then set the course1 to 4
I want at highest 4 results/course instances which I later order by the period of the year
declare myCursor1 CURSOR
for SELECT top 4 period from Course instance
where year = #year
open myCursor1
fetch next from myCursor1 into #variable
--print #variable
while ##fetch_status = 0
Begin
UPDATE #Table2
SET InstanceCourse1 = #variable
where current of myCursor1
fetch next from myCursor1 into #variable
print #variable
End
Close myCursor1
deallocate myCursor1
insert into #table1
select 'Firstname', 'Lastname'
insert into #table1
select Firstname, Lastname from staff order by Lastname
END
select * from #Table1 -- for testing purposes
select * from #Table2 -- for testing purposes
--Then i want to combine these tables into the output at the top
This is how far I've gotten, I don't know how to get the courses into the columns and then get the amount of hours for each staff member.
If anyone can help guide me in the right direction I would be very grateful. My idea about the cursor was to get the top (0-4) values from the top4 course periods during that year and then add them to the #table2.

Answer 1

Ok. This is not pretty. It is a really ugly dynamic sql, but in my testing it seems to be working. I have created an extra subquery to get the courses values as the first row and then Union with the rest of the result. The top four courses are gathered by using ROW_Number() and order by Year and period. I had to make different versions of the courses string I am creating in order to use them for both column names, and in my pivot. Give it a try. Hopefully it will work on your data as well.
DECLARE #Year INT
SET #Year = 2014
DECLARE #Query NVARCHAR(2000)
DECLARE #CoursesColumns NVARCHAR(2000)
SET #CoursesColumns = (SELECT '''' + Course + ''' as c' + CAST(ROW_NUMBER() OVER(ORDER BY Year, Period) AS nvarchar(50)) + ',' AS 'data()'
FROM AttendedBy where [Year] = #Year
for xml path(''))
SET #CoursesColumns = LEFT(#CoursesColumns, LEN(#CoursesColumns) -1)
SET #CoursesColumns =
CASE
WHEN CHARINDEX('c1', #CoursesColumns) = 0 THEN #CoursesColumns + 'NULL as c1, NULL as c2, NULL as c3, NULL as c4'
WHEN CHARINDEX('c2', #CoursesColumns) = 0 THEN #CoursesColumns + ',NULL as c2, NULL as c3, NULL as c4'
WHEN CHARINDEX('c3', #CoursesColumns) = 0 THEN #CoursesColumns + ', NULL as c3, NULL as c4'
WHEN CHARINDEX('c4', #CoursesColumns) = 0 THEN #CoursesColumns + ', NULL as c4'
ELSE #CoursesColumns
END
DECLARE #Courses NVARCHAR(2000)
SET #Courses = (SELECT Course + ' as c' + CAST(ROW_NUMBER() OVER(ORDER BY Year, Period) AS nvarchar(50)) + ',' AS 'data()'
FROM AttendedBy where [Year] = #Year
for xml path(''))
SET #Courses = LEFT(#Courses, LEN(#Courses) -1)
SET #Courses =
CASE
WHEN CHARINDEX('c1', #Courses) = 0 THEN #Courses + 'NULL as c1, NULL as c2, NULL as c3, NULL as c4'
WHEN CHARINDEX('c2', #Courses) = 0 THEN #Courses + ',NULL as c2, NULL as c3, NULL as c4'
WHEN CHARINDEX('c3', #Courses) = 0 THEN #Courses + ', NULL as c3, NULL as c4'
WHEN CHARINDEX('c4', #Courses) = 0 THEN #Courses + ', NULL as c4'
ELSE #Courses
END
DECLARE #CoursePivot NVARCHAR(2000)
SET #CoursePivot = (SELECT Course + ',' AS 'data()'
FROM AttendedBy where [Year] = #Year
for xml path(''))
SET #CoursePivot = LEFT(#CoursePivot, LEN(#CoursePivot) -1)
SET #Query = 'SELECT Name, LastName, c1, c2, c3, c4
FROM (
SELECT ''Name'' as name, ''LastName'' as lastname, ' + #CoursesColumns +
' UNION
SELECT Name, LastName,' + #Courses +
' FROM(
SELECT
s.Name
,s.LastName
,ci.Course
,ci.Year
,ci.Period
,CAST(ab.Hours AS NVARCHAR(100)) AS Hours
FROM Staff s
LEFT JOIN AttendedBy ab
ON
s.SSN = ab.SSN
LEFT JOIN CourseInstance ci
ON
ab.Course = ci.Course
WHERE ci.Year=' + CAST(#Year AS nvarchar(4)) +
' ) q
PIVOT(
MAX(Hours)
FOR
Course
IN (' + #CoursePivot + ')
)q2
)q3'
SELECT #Query
execute(#Query)
Edit: Added some where clauses so only courses from given year is shown. Added Screenshot of my results.

Answer 2

try this
DECLARE #CourseNameString varchar(max),
#query AS NVARCHAR(MAX);
SET #CourseNameString=''
select #CourseNameString = STUFF((SELECT distinct ',' + QUOTENAME(Course)
FROM Attended where [Year]= 2013
FOR XML PATH(''), TYPE
).value('.', 'NVARCHAR(MAX)')
,1,1,'')
set #query = '
select Name,LastName,'+#CourseNameString+' from Staff as e inner join (
SELECT * FROM
(SELECT [Hours],a.SSN,a.Course as c FROM Attended as a inner JOIN Staff as s
ON s.SSN = s.SSN) p
PIVOT(max([Hours])FOR c IN ('+#CourseNameString+')) pvt)p
ON e.SSN = p.SSN'
execute(#query)

Answer 3

Use subquery like this one :
SELECT Firstname, Lastname, (select instanceCourse1 from table2) as InstanceCourse1 from Table1