SQL Query - Rows to Columns but without pivot - sql

Question

I need an efficient way to convert the data returned in rows to columns for a football database I'm working on.
2 tables, one holding fixtures, one holding predictions.
Fixtures:
Predictions
I would like the data in those two table returned as follows (Can't post another link, but this query will give you an idea):
SELECT 1 as UserID,
2 as [Stoke vs Man United],
1 as [Bournemouth vs Crystal Palace],
2 as [Swansea vs West Brom],
1 as [Chelsea vs Watford],
3 as [Liverpool vs Leicester],
1 as [Tottenham vs Norwich],
2 as [Aston Villa vs West Ham]
The problem is, each week, the chosen teams will change so I couldn't get a pivot query to work. Any ideas?

Answer 1

2 things you need to know about to make this work.
Dynamic Pivot
sp_executesql
Example
-- Param Definitions
DECLARE #Sql NVARCHAR(MAX),
#Columns NVARCHAR(MAX),
#WeekNo INT = 6,
#UserID INT = 1,
#Params NVARCHAR(MAX) = N'#Week INT, #User INT'
-- Dynamic Column Names
SELECT #Columns = COALESCE(#Columns + ',','') + QUOTENAME(HomeTeamName + ' vs ' + AwayTeamName)
FROM usr_SS_Fixtures
WHERE WeekNo = #WeekNo
-- Dynamic SQL
SET #Sql = N'
SELECT *
FROM
(
SELECT
pred.UserId,
pred.ResultCode,
CONCAT(HomeTeamName,'' vs '', AwayTeamName) AS Teams
FROM
usr_SS_Fixtures fix
JOIN usr_SS_Predictions pred ON fix.EventID = pred.EventID AND fix.WeekNo = pred.WeekNo
WHERE
fix.WeekNo = #Week
AND pred.UserID = #User
) t
PIVOT
(
MAX(ResultCode)
FOR Teams IN (' + #Columns + ')
) p
'
-- Executes the dynamic SQL
EXECUTE sp_executesql #Sql, #Params, #Week = #WeekNo, #User = #UserID
DEMO

Answer 2

You have an interesting variation on the normal dynamic pivot problem, due to the known-in-advance maximum number of games, that makes one possible solution a little simpler. Try the SQL below; it creates a first row that contains the desired column headings, which may be sufficient for simple display purposes.
declare #weekNo as int = 6
,#UserID as int = 1;
with
fixture(UserID, EventID, [Value], GameNo) as (
select -1, EventID, AwayTeamName + ' at ' + HomeTeamName
, row_number() over (partition by WeekNo order by EventID)
from usr_SS_Fixtures
),
prediction(UserID, EventID, [Value], GameNo) as (
select UserID, EventID, ResultCode
, row_number() over (partition by WeekNo order by EventID)
from usr_SS_Predictions
),
data as (
select
WeekNo, UserID
,[1],[2],[3],[4],[5],[6],[7]
from (
select WeekNo, UserID, EventID, [Value] from fixture
union all
select WeekNo, UserID, EventID, [Value] from prediction
) T
pivot (
max([Value]) for GameNo in ([1],[2],[3],[4],[5],[6],[7])
) pvt
)
select
UserID,[1],[2],[3],[4],[5],[6],[7]
from data
where WeekNo = #WeekNo
order by
UserID