Pivot Table SQL server 2008 - sql

Question

I can't get to grips with pivot tables, I have 3 tables:
AccidentType:
AccidentTypeID Description
1 Type1
2 Type2
3 Type3
4 Type4
CaseAccidentType:
AccidentTypeID CaseID
1 1000
2 1000
3 1001
Case:
CaseID Name
1000 Case A
1001 Case B
Case is the main table with caseaccidenttype as a link table to the accident type. Each case can have multiple accidenttypes.
I want something like:
CaseID Name Type1 Type2 Type3 Type4
1000 Case A True True False False
1001 Case B False False True False
Looks like a pivot table but i just cant figure it out.
Update:
There will be many AccidentTypes is it possible to dynamically generate the column headings.

Answer 1

Test Data
DECLARE #AccidentType TABLE(AccidentTypeID INT, [Description] NVARCHAR(100))
INSERT INTO #AccidentType VALUES
(1,'Type1'),(2,'Type2'),(3,'Type3'),(4,'Type4')
DECLARE #CaseAccidentType TABLE(AccidentTypeID INT,CaseID INT)
INSERT INTO #CaseAccidentType VALUES
(1,1000),(2,1000),(3,1001)
DECLARE #Case TABLE(CaseID INT, Name NVARCHAR(100))
INSERT INTO #Case VALUES
(1000,'Case A'),(1001,'Case B')
Query
;With CTE
AS(
SELECT *
FROM
(
SELECT C.CaseID,C.Name, AT.[Description]
FROM #Case C INNER JOIN #CaseAccidentType CAT
ON C.CaseID = CAT.CaseID
INNER JOIN #AccidentType AT
ON CAT.AccidentTypeID = AT.AccidentTypeID
) Q
PIVOT
(MAX(Name)
FOR [Description]
IN ([Type1],[Type2],[Type3],[Type4])
)Pv
)
SELECT CT.CaseID
,C.Name
,CASE WHEN CT.Type1 IS NOT NULL THEN 'TRUE' ELSE 'FALSE' END AS Type1
,CASE WHEN CT.Type2 IS NOT NULL THEN 'TRUE' ELSE 'FALSE' END AS Type2
,CASE WHEN CT.Type3 IS NOT NULL THEN 'TRUE' ELSE 'FALSE' END AS Type3
,CASE WHEN CT.Type4 IS NOT NULL THEN 'TRUE' ELSE 'FALSE' END AS Type4
FROM CTE CT INNER JOIN #Case C
ON CT.CaseID = C.CaseID
Result Set
╔════════╦════════╦═══════╦═══════╦═══════╦═══════╗
║ CaseID ║ Name ║ Type1 ║ Type2 ║ Type3 ║ Type4 ║
╠════════╬════════╬═══════╬═══════╬═══════╬═══════╣
║ 1000 ║ Case A ║ TRUE ║ TRUE ║ FALSE ║ FALSE ║
║ 1001 ║ Case B ║ FALSE ║ FALSE ║ TRUE ║ FALSE ║
╚════════╩════════╩═══════╩═══════╩═══════╩═══════╝

Answer 2

Another approach -
SELECT C.CaseID,C.[Name],AT.[Description]
INTO #NO_PIVOT
FROM [Case] C
INNER JOIN CaseAccidentType CAT
ON CAT.CaseID = C.CaseID
INNER JOIN AccidentType AT
ON AT.AccidentTypeID = CAT.AccidentTypeID
SELECT
CaseID
,[Name]
,CASE WHEN SUM(Type1) > 0 THEN CAST('True' AS VARCHAR(5)) ELSE 'False' END AS [Type1]
,CASE WHEN SUM(Type2) > 0 THEN CAST('True' AS VARCHAR(5)) ELSE 'False' END AS [Type2]
,CASE WHEN SUM(Type3) > 0 THEN CAST('True' AS VARCHAR(5)) ELSE 'False' END AS [Type3]
,CASE WHEN SUM(Type4) > 0 THEN CAST('True' AS VARCHAR(5)) ELSE 'False' END AS [Type4]
FROM
( SELECT
CaseID
,[Name]
,CASE WHEN [Description] = 'Type1' AND ISNULL((SELECT COUNT(1) FROM #NO_PIVOT WHERE CaseID = NP.CaseID AND [Name] = NP.[Name]),-1) > 0
THEN 1 ELSE 0 END AS [Type1]
,CASE WHEN [Description] = 'Type2' AND ISNULL((SELECT COUNT(1) FROM #NO_PIVOT WHERE CaseID = NP.CaseID AND [Name] = NP.[Name]),-1) > 0
THEN 1 ELSE 0 END AS [Type2]
,CASE WHEN [Description] = 'Type3' AND ISNULL((SELECT COUNT(1) FROM #NO_PIVOT WHERE CaseID = NP.CaseID AND [Name] = NP.[Name]),-1) > 0
THEN 1 ELSE 0 END AS [Type3]
,CASE WHEN [Description] = 'Type4' AND ISNULL((SELECT COUNT(1) FROM #NO_PIVOT WHERE CaseID = NP.CaseID AND [Name] = NP.[Name]),-1) > 0
THEN 1 ELSE 0 END AS [Type4]
FROM #NO_PIVOT NP
)RESULTSET
GROUP BY CaseID, [Name]