SQL query using if else

My SQL code looks like this:

SELECT 
    Scores.PupilId, Scores.BoysName, Scores.FormGroup,
    IF (Scores.FormGroup = "10SB", "Great", "ok")
FROM 
    Scores

I get this message

no such function: if: SELECT Scores.PupilId, Scores.BoysName, Scores.FormGroup,
if(Scores.FormGroup="10SB","Great","ok")
FROM Scores

This is flat file database