Trigger, SQL SERVER 2008 - sql

Question

i have two tables
PaymentData
Ser Customerid Totalpaid
1. AGP001 2400
2. AGP002 1000
3. AGP003 1500
Receipt
Receipt# Customerid Paid
1. AGP001 1200
2. AGP001 1200
I want to create a trigger on Receipt table, and trigger will fire on insert, update, and delete operations which updates the totalpaid field of PaymentData table. Everytime a new Receipt record is inserted or updated against some customerid, totalpaid field for that customer will updated as well.
Trigger should do following.
Update PaymentData.totalpaid = sum(Recipt.paid)
where Receipt.customerID = PaymentData.customerID

Answer 1

I guess you need some trigger like:
CREATE TRIGGER dbo.OnReceiptUpdate
ON dbo.Receipt
AFTER INSERT,DELETE,UPDATE --operations you want trigger to fire on
AS
BEGIN
SET NOCOUNT ON;
DECLARE #customer_id VARCHAR(10)
SET #customer_id= COALESCE
(
(SELECT customer_id FROM inserted), --table inserted contains inserted rows (or new updated rows)
(SELECT customer_id FROM deleted) --table deleted contains deleted rows
)
DECLARE #total_paid DECIMAL
SET #total_paid =
(
SELECT SUM(paid)
FROM Receipt
WHERE customer_id = #customer_id
)
UPDATE PaymentData
SET total_paid = #total_paid
WHERE customer_id = #customer_id
IF ##ROWCOUNT = 0 --if nothing was updated - you don't have record in PaymentData, so make it
INSERT INTO PaymentData (customer_id, total_paid)
VALUES (#customer_id, #total_paid)
END
GO
Keep in mind - it aint gonna work with multiply updates/deletes/inserts - This is just example of how you need to do it

Answer 2

Try this trigger with multiply updates, inserts or deletes.
CREATE TRIGGER [dbo].upd_PaymentData ON dbo.Receipt
FOR INSERT, UPDATE, DELETE
AS
IF ##ROWCOUNT = 0 return
SET NOCOUNT ON;
DECLARE #actionTable nvarchar( 10),
#insCount int = (SELECT COUNT(*) FROM inserted),
#delCount int = (SELECT COUNT(*) FROM deleted)
SELECT #actionTable = CASE WHEN #insCount > #delCount THEN 'inserted'
WHEN #insCount < #delCount THEN 'deleted' ELSE 'updated' END
IF #actionTable IN ('inserted', 'updated')
BEGIN
;WITH cte AS
(
SELECT r.Customerid, SUM(r.Paid) AS NewTotalPaid
FROM dbo.Receipt r
WHERE r.Customerid IN (SELECT i.Customerid FROM inserted i)
GROUP BY r.Customerid
)
UPDATE p
SET p.Totalpaid = c.NewTotalPaid
FROM dbo.PaymentData p JOIN cte c ON p.Customerid = c.Customerid
END
ELSE
BEGIN
;WITH cte AS
(
SELECT d.Customerid, SUM(ISNULL(r.Paid, 0)) AS NewTotalPaid
FROM deleted d LEFT JOIN dbo.Receipt r ON d.Customerid = r.Customerid
GROUP BY d.Customerid
)
UPDATE p
SET p.Totalpaid = c.NewTotalPaid
FROM dbo.PaymentData p JOIN cte c ON p.Customerid = c.Customerid
END

Answer 3

CREATE TRIGGER [dbo].upd_PaymentData ON dbo.Receipt
FOR INSERT, UPDATE, DELETE
AS
IF ##ROWCOUNT = 0 return
SET NOCOUNT ON;
DECLARE #actionTable nvarchar( 10),
#insCount int = (SELECT COUNT(*) FROM inserted),
#delCount int = (SELECT COUNT(*) FROM deleted)
SELECT #actionTable = CASE WHEN #insCount > #delCount THEN 'inserted'
WHEN #insCount < #delCount THEN 'deleted' ELSE 'updated' END
IF #actionTable IN ('inserted', 'updated')
BEGIN
;WITH cte AS
(
SELECT r.Customerid, SUM(r.Paid) AS NewTotalPaid,<strike> r.paymentDate</strike>
FROM dbo.Receipt r
WHERE r.Customerid IN (SELECT i.Customerid FROM inserted i)
GROUP BY r.Customerid
)
UPDATE p
SET p.Totalpaid = c.NewTotalPaid
<strike>SET p.lastpaymentDate = c.paymentDate</strike>
FROM dbo.PaymentData p JOIN cte c ON p.Customerid = c.Customerid
END
ELSE
BEGIN
;WITH cte AS
(
SELECT d.Customerid, SUM(ISNULL(r.Paid, 0)) AS NewTotalPaid
FROM deleted d LEFT JOIN dbo.Receipt r ON d.Customerid = r.Customerid
GROUP BY d.Customerid
)
UPDATE p
SET p.Totalpaid = c.NewTotalPaid
FROM dbo.PaymentData p JOIN cte c ON p.Customerid = c.Customerid
END
I tried to add more functionality as indicated inside tage but it gives error and is not working.
Simply added one field in both tables.
In paymentdata added lastpaymentdate,
And in receipt added paymentdate.
On inserting or updating receipt table, paymentdata.lastpaymentdate should also update to receipt.paymentdate.