sql and c# - update if exists, else insert

I am using MySqlCommand in MySqlConnection in a WinForms C# application to insert data into my database.

NOTE: lets say ALL names are unique, no matter what!!

how can I update a row if the column value in "name" already exists in database?

and if it does not exist, i want to insert new row.

Here is my code now:

command.CommandText = @"
    INSERT INTO users (name, age, job)
    VALUES (@name, @age, @job)
    ON DUPLICATE KEY UPDATE users SET age = @age, job = @job
";

I already set values to @name, @age and @job like this:

command.Parameters.AddWithValue("@name", Users.Name);

I want to check, if @name already exists in the "name" column in the database. So if @name is "John", it should check if "John" already exists.

And if exists, I only want to update the age and job on that row.

And if "John" does not exist, insert the full row with name+age+job.

This code gives me an error like this:

An exception of type 'MySql.Data.MySqlClient.MySqlException' occurred in mscorlib.dll but was not handled in user code

You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'ON DUPLICATE KEY UPDATE users SET age = 50, job =' at line 1