MERGE - to replace ON Duplicate with sql server - sql

Question

I've predominantly used mySQL so moving over to azure and sql server I realise that on duplicate does not work.
I'm trying to do this:
INSERT INTO records (jid, pair, interval, entry) VALUES (1, 'alpha', 3, 'unlimited') ON DUPLICATE KEY UPDATE entry = "limited";
But of course on duplicate key isn't allowed here. So MERGE is the right form.
I've looked at:
https://technet.microsoft.com/en-gb/library/bb522522(v=sql.105).aspx
But honestly the example is a bit excessive and eye watering. Could someone dumb it down for me to fit my example so I can understand it better?

Answer 1

In order to do the merge you need some form of source table/table var for the merge statement. Then you can do the merging. So something along the lines of this maybe (note: not completely syntax checked, apologies in advance):
WITH src AS (
-- This should be your source
SELECT 1 AS Id, 2 AS Val
)
-- The above is not neccessary if you have a source table
MERGE Target -- the detination table, so in your case records
USING src -- as defined above
ON (Target.Id = src.Id) -- how do we join the tables
WHEN NOT MATCHED BY TARGET
-- if we dont match, what do to the destination table. This case insert it.
THEN INSERT(Id, Val) VALUES(src.Id, src.Val)
WHEN MATCHED
-- what do we do if we match. This case update Val
THEN UPDATE SET Target.Val = src.Val;
Don't forget to read the proper syntax page: https://msdn.microsoft.com/en-us/library/bb510625.aspx
I think this translates to your example (tm):
WITH src AS (
-- This should be your source
SELECT 1 AS jid, 'alpha' AS pair, 3 as 'interval'
)
MERGE records -- the detination table, so in your case records
USING src -- as defined above
ON (records.Id = src.Id) -- how do we join the tables
WHEN NOT MATCHED BY TARGET
-- if we dont match, what do to the destination table. This case insert it.
THEN INSERT(jid, pair, interval, entry) VALUES(src.jid, src.pair, src.interval, 'unlimited')
WHEN MATCHED
-- what do we do if we match. This case update Val
THEN UPDATE SET records.entry = 'limited';