Insert into a MySQL table or update if exists

I want to add a row to a database table, but if a row exists with the same unique key I want to update the row.

For example,

insert into table (id, name, age) values(1, "A", 19)

Let’s say the unique key is id, and in my database there is a row with id = 1. In that case I want to update that row with these values. Normally this gives an error. If I use insert IGNORE it will ignore the error, but it still won’t update