CREATE TABLE student (id INTEGER, name TEXT, score INTEGER);
INSERT INTO student VALUES (1, 'Mo', 92), (2, 'Sara', 74), (3, 'Ken', 58);
-- CASE picks the first matching branch
SELECT name, score,
  CASE
    WHEN score >= 90 THEN 'A'
    WHEN score >= 70 THEN 'B'
    ELSE 'C'
  END AS grade
FROM student;

CASE returns a value per condition