After Trigger with JOIN Tables - sql

Question

TASK: Create an AFTER TRIGGER to accomplish a condition from a JOIN. The Trigger would be in table_1 when some record is created. Meanwhile, table_2 has a common column with some parameters that the condition needs to have.
Every time that the Result <> 1 AND Status <> 3 in table_2 and ALERT should be sent
-- QUERY WITH JOIN TABLE_1 ON TABLE_2
-- MOCK TABLE
-- Table_1 as A | Table_2 as B
A.LotCode | A.LineNumber | B.Result | B.Status
00000 | xxxx | 1 | 3
00001 | xxxx | 2 | 4
-- The LotCode 00001 should send it through email because satisfy the condition
CREATE TRIGGER FullfillOrderQCResult
ON Table_1
AFTER INSERT
AS
BEGIN
-----DECLARE VARIABLES-----
DECLARE #LOTNUMBER VARCHAR(50)
DECLARE #ACTIONPEFORMED VARCHAR(MAX)
DECLARE #ITEM INT
DECLARE #RESULT TINYINT
DECLARE #STATUS TINYINT
SELECT #LOTNUMBER = A.LotCode, #ITEM = A.LineNumber, #RESULT = B.Result, #STATUS = B.Status
FROM inserted AS A
JOIN Table_2 AS B
ON A.LotCode = B.DocumentID2
-----CONDITION WHEN I INSERT A VALUE-----
IF (#RESULT <> 1 AND #STATUS <> 3)
BEGIN
SET #ACTIONPEFORMED =
N'Hello, ' + '<br>' + '<br>'
+ N' The following LOT NUMBER: ' + #LOTNUMBER + ' has not been approved for this Item: '
EXEC MSDB.DBO.SP_SEND_DBMAIL
#PROFILE_NAME = 'SQLMail',
#RECIPIENTS = 'TEST#gmail.com',
#SUBJECT = 'LOT NON-Approved',
#BODY = #ACTIONPEFORMED,
#IMPORTANCE = 'HIGH',
#BODY_FORMAT = 'HTML'
END
ELSE
PRINT 'ALL GOOD MY FRIEND'
END
TESTING THE TRIGGER
--------INSERT VALUES------------------
INSERT INTO Table_1 (LotCode,LineNumber)
values ('00000','xxxx')
-----EXISTING VALUES-----
INSERT INTO Table_2 (CreationUser,DocumentID1,DocumentID2,DocumentID3,Result,Status)
values ('JL','00000','00000','00000',2,3)

Answer 1

The following shows you how to handle the fact that Inserted might have multiple rows. This is really not ideal behaviour for a trigger, because you have to process the results RBAR (row by agonising row), which is slow by itself, let alone the fact that you are sending an email.
CREATE TRIGGER FullfillOrderQCResult
ON Table_1
AFTER INSERT
AS
BEGIN
SET NOCOUNT ON;
-----DECLARE VARIABLES-----
DECLARE #ACTIONPEFORMED varchar(max), #Id int;
SELECT A.LotCode, A.LineNumber, CONVERT(bit, 0) Done, IDENTITY(int) id -- Use your own id if you have one, just need to uniquely identify each row.
INTO #FullfillOrderQCResult_temp
FROM Inserted AS A
INNER JOIN Table_2 AS B ON A.LotCode = B.DocumentID2
WHERE B.Result <> 1 and B.[Status] <> 3;
WHILE EXISTS (SELECT 1 FROM #FullfillOrderQCResult_temp WHERE Done = 0) BEGIN
SELECT TOP 1 #Id = id, #ACTIONPEFORMED =
N'Hello, ' + '<br>' + '<br>'
+ N'The following LOT NUMBER: ' + LotCode + ' has not been approved for this Item: ' + LineNumber
FROM #FullfillOrderQCResult_temp
WHERE Done = 0;
EXEC MSDB.DBO.SP_SEND_DBMAIL
#PROFILE_NAME = 'SQLMail',
#RECIPIENTS = 'TEST#gmail.com',
#SUBJECT = 'LOT NON-Approved',
#BODY = #ACTIONPEFORMED,
#IMPORTANCE = 'HIGH',
#BODY_FORMAT = 'HTML';
UPDATE #FullfillOrderQCResult_temp SET Done = 1 WHERE id = #Id;
END;
END;
I don't know whether you would still want the concept of 'ALL GOOD MY FRIEND' because you could have none, some or all rows with issues. Anyway I assume print is only for debugging.
That said you would be much better off pushing an event into a queue and having a service process said event because triggers really should be as fast as possible. And adding an event to a queue could be handled in a set based manner e.g.
CREATE TRIGGER FullfillOrderQCResult
ON Table_1
AFTER INSERT
AS
BEGIN
SET NOCOUNT ON;
INSERT INTO MyEventQueue (A.LotCode, A.LineNumber) -- Any other information required to identify the records etc
SELECT A.LotCode, A.LineNumber
FROM Inserted AS A
INNER JOIN Table_2 AS B ON A.LotCode = B.DocumentID2
WHERE B.Result <> 1 and B.[Status] <> 3;
END;