MSSQL INSERT OR UPDATE if EXISTS

Need to insert a row if its not exist and update if exists. I've found this solution for MySQL:

INSERT INTO table (id, name, age) VALUES(1, "A", 19) ON DUPLICATE KEY UPDATE

name="A", age=19

But I can't find similar for MSSQL..

Solution

You can use 2 statements (INSERT + UPDATE) in the following order. The update won't update anything if it doesn't exist, the insert won't insert if it exist:

UPDATE T SET
    name = 'A',
    age = 19
FROM
    [table] AS T
WHERE
    T.id = 1

INSERT INTO [table] (
    id,
    name,
    age)
SELECT
    id = 1,
    name = 'A',
    age = 19
WHERE
    NOT EXISTS (SELECT 'not yet loaded' FROM [table] AS T WHERE T.id = 1)

Or a MERGE:

;WITH ValuesToMerge AS
(
    SELECT
        id = 1,
        name = 'A',
        age = 19
)
MERGE INTO 
    [table] AS T
USING
    ValuesToMerge AS V ON (T.id = V.id)
WHEN NOT MATCHED BY TARGET THEN
    INSERT (
        id,
        name,
        age)
    VALUES (
        V.id,
        V.name,
        V.age)
WHEN MATCHED THEN
    UPDATE SET
        name = V.name,
        age = V.name;