Trigger to update table according to user rank - sql

Question

I'm a stranger to SQL Server Triggers.
I ended up having a problem like this. Please have a look.
I have two tables 'users' & 'test'
CREATE TABLE users(
email VARCHAR(250),
rank FLOAT
);
CREATE TABLE test(
score INT,
total INT
);
I need to create a trigger to;
2.1 Update users rank by the value of avg ( avg = test.score / test.total)
2.2 Here's What I tried so far:
CREATE TRIGGER auto_rank ON dbo.test FOR INSERT
BEGIN
DECLARE #sc INT
DECLARE #tot INT
DECLARE #avg FLOAT
#tot = SELECT inserted.total FROM dbo.test
#sc = SELECT inserted.score FROM dbo.test
SET #avg=#sc/#tot
UPDATE dbo.users SET rank=#avg WHERE email=inserted.email
END

Answer 1

You missing the email in test from your table design, but it should have such column per your code:
UPDATE dbo.users SET rank=#avg WHERE email=inserted.email
Then you need a view instead of trigger in this case:
Create view user as (select email, score/total as rank from test group by email);
Hope this help.

Answer 2

Try this :
CREATE TRIGGER auto_rank ON dbo.test FOR INSERT
BEGIN
UPDATE a SET a.rank=b.rn
from
users a
inner join
(select email,inserted.score/inserted.total rn from inserted)b
on a.email=b.email
END
I have not tested this, but this should work fine.

Answer 3

You need to modify your tables so that the test table contains the email column:
CREATE TABLE test(score INT,
total INT,
email varchar(250)
);
Then you can create the trgiger like this:
CREATE TRIGGER [dbo].[auto_rank] ON [dbo].[test]
FOR INSERT
AS
BEGIN
DECLARE MyCursor CURSOR FOR
SELECT score, total, email FROM Inserted
DECLARE #sc INT
DECLARE #tot INT
DECLARE #email VARCHAR(30)
DECLARE #avg FLOAT
DECLARE #MSG VARCHAR(50)
OPEN MyCursor;
FETCH NEXT FROM MyCursor INTO #sc, #tot, #email
WHILE ##FETCH_STATUS = 0
BEGIN
SELECT #avg=#sc/#tot
UPDATE users SET rank=#avg WHERE users.email=#email
SELECT #MSG = 'email Updated ' + #email + '. New Rank is ' + Str(#avg, 25, 5);
PRINT #MSG
FETCH NEXT FROM MyCursor
END;
CLOSE MyCursor;
DEALLOCATE MyCursor;
END

Answer 4

Sorry for being so late to continue this thread but, I'm happy to say that I found the answer. it's because of you all.
So, here's what i did;
first;
CREATE TABLE users(
email VARCHAR(250),
rank FLOAT,
constraint pk_users PRIMARY KEY(email)
);
CREATE TABLE test(
email VARCHAR(250),
score INT,
total INT,
constraint pk_test PRIMARY KEY(email),
constraint fk_from_users FOREIGN KEY(email) references users(email)
);
create trigger trig_ex02 on dbo.test
after insert
as
begin
declare #score FLOAT
declare #total FLOAT
declare #average FLOAT
declare #msg varchar(100)
declare #email varchar(250)
set #email = (select email from inserted)
set #score = (select score from inserted)
set #total = (select total from inserted)
set #average =(#score/#total)
select #msg = 'SCORE IS'+ str(#score)+'TOTAL IS'+str(#total)+' AVERAGE IS ' +str(#average,25,5)+' END '
print #msg
UPDATE users SET rank=#average WHERE users.email=#email
end;