Sql Server - INSERT INTO SELECT to avoid duplicates
- by Ashish Gupta
I have following two tables:-
Table1
-------------
ID Name
1 A
2 B
3 C
Table2
--------
ID Name
1 Z
I need to insert data from Table1 to Table2 and I can use following sytax for the same:-
INSERT INTO Table2(Id, Name) SELECT Id, Name FROM Table1
However, In my case duplicate Ids might exist in Table2 (In my case Its Just "1") and I dont want to copy that again as that would throw an error.
I can write something like this:-
IF NOT EXISTS(SELECT 1 FROM Table2 WHERE Id=1)
INSERT INTO Table2 (Id, name) SELECT Id, name FROM Table1
ELSE
INSERT INTO Table2 (Id, name) SELECT Id, name FROM Table1 WHERE Table1.Id<>1
Is there a better way to do this without using IF - ELSE? I want to avoid two INSERT INTO-SELECT statements based on some condition.
Any help is appreciated.
