How to update multiple rows with one MS SQL query?

Question

Transact SQL

Hello! There is a table with two rows:

I need to update either one row or both at the same time, and in each case the Lat and Lng fields are updated together. Wrote a request:

INSERT INTO MyGMap (id, Lat, Lng) VALUES (1,'1','2'), (2,'3','4') ON DUPLICATE KEY UPDATE id = VALUES(id), Lat=VALUES(Lat), Lng=VALUES(Lng)

Gives an error that "invalid syntax near ON", and also underlines VALUES, id, Lat and Lng. Tell me what's wrong?

Answer 1

UPDATE Markers
SET Lat = CASE ID WHEN 1 THEN '1' WHEN 2 THEN '3' END,
    Lng = CASE ID WHEN 1 THEN '2' WHEN 2 THEN '4' END
WHERE ID IN (1, 2)

Answer 2

Update?

UPDATE MyGMap
SET Lat = '1', Lng = '2'
WHERE Id IN (1, 2);

Or add?

INSERT INTO MyGMap (Lat, Lng)
VALUES ('1', '2'), ('3', '4');

UPD:

UPDATE MyGMap as row_1 INNER JOIN MyGMap as row_2
ON
  row_1.id = 1 AND
  row_2.id = 2
SET
  row_1.Lat = '1',
  row_1.Lng = '2',
  row_2.Lat = '3',
  row_3.Lng = '4';