Case statement with grouping - sql

Question

Can you help me write a SELECT statement that returns a single row having columns for each TypeId involved for the transaction number 55?
CREATE TABLE Types
(
Id INT IDENTITY(1,1) NOT NULL,
Name VARCHAR(100) NOT NULL,
CONSTRAINT PK_Types PRIMARY KEY CLUSTERED(Id)
)
GO
INSERT INTO Types
VALUES
('Type1')
,('Type2')
,('Type3')
,('Type4')
,('Type5')
GO
CREATE TABLE Transactions
(
Id INT IDENTITY(1000,1) NOT NULL,
TypeId INT NULL,
TransactionNumber INT NOT NULL,
Amount MONEY NULL,
DateRecorded DATETIME2 NOT NULL,
CONSTRAINT PK_Transactions PRIMARY KEY CLUSTERED(Id),
CONSTRAINT FK_Types FOREIGN KEY(TypeId) REFERENCES Types(Id)
)
GO
INSERT INTO Transactions
VALUES
(1,55,2555.50,SYSDATETIME())
,(3,55,3555.50,SYSDATETIME())
,(4,55,4555.50,SYSDATETIME())
,(5,55,5555.50,SYSDATETIME())
GO
I need a single row returned for each transaction number in the Transactions table.
What I already tried:
SELECT TransactionNumber
,(CASE WHEN TypeId = 1 THEN Amount ELSE 0 END) AS Type1
,(CASE WHEN TypeId = 2 THEN Amount ELSE 0 END) AS Type2
,(CASE WHEN TypeId = 3 THEN Amount ELSE 0 END) AS Type3
,(CASE WHEN TypeId = 4 THEN Amount ELSE 0 END) AS Type4
,(CASE WHEN TypeId = 5 THEN Amount ELSE 0 END) AS Type5
FROM Transactions

Answer 1

SELECT TransactionNumber
,sum(CASE WHEN TypeId = 1 THEN Amount ELSE 0 END) AS Type1
,sum(CASE WHEN TypeId = 2 THEN Amount ELSE 0 END) AS Type2
,sum(CASE WHEN TypeId = 3 THEN Amount ELSE 0 END) AS Type3
,sum(CASE WHEN TypeId = 4 THEN Amount ELSE 0 END) AS Type4
,sum(CASE WHEN TypeId = 5 THEN Amount ELSE 0 END) AS Type5
FROM Transactions group by TransactionNumber;

Answer 2

I think you can do a PIVOT to get required output:
SELECT *
FROM (
SELECT ty.NAME, ISNULL(Amount,0)Amount
FROM TRANSACTIONS t
INNER JOIN Types ty ON ty.Id = t.TypeId
WHERE TransactionNumber = 55
) sub
PIVOT(
SUM(Amount) FOR [Name] IN ([Type1], [Type2], [Type3], [Type4], [Type5])
) AS pivottable
SQL Fiddle

Answer 3

With conditional aggregation:
select Id,
sum(case TypeId when 1 then Amount end) Type1,
sum(case TypeId when 2 then Amount end) Type2,
...
from Transactions
group by Id

Answer 4

I think this would be the query you are looking for:
SELECT
COUNT(CASE WHEN TypeID = 1 THEN 1 ELSE NULL END) '# Transactions Type 1'
, COUNT(CASE WHEN TypeID = 2 THEN 1 ELSE NULL END) '# Transactions Type 2'
, COUNT(CASE WHEN TypeID = 3 THEN 1 ELSE NULL END) '# Transactions Type 3'
, COUNT(CASE WHEN TypeID = 4 THEN 1 ELSE NULL END) '# Transactions Type 4'
, COUNT(CASE WHEN TypeID = 5 THEN 1 ELSE NULL END) '# Transactions Type 5'
FROM TRANSACTIONS
Where TransactionNumber = 55
You can find a working SQLFiddle here.
EDIT:
After you comment I think what you are actually looking for is SUM().
SELECT TransactionNumber
, SUM(CASE WHEN TypeId = 1 THEN Amount ELSE 0 END) AS Type1
, SUM(CASE WHEN TypeId = 2 THEN Amount ELSE 0 END) AS Type2
, SUM(CASE WHEN TypeId = 3 THEN Amount ELSE 0 END) AS Type3
, SUM(CASE WHEN TypeId = 4 THEN Amount ELSE 0 END) AS Type4
, SUM(CASE WHEN TypeId = 5 THEN Amount ELSE 0 END) AS Type5
FROM Transactions
GROUP BY TransactionNumber
SQLFiddle for 2nd query here.