mysql if返回多列

IF(condition, value_if_true, value_if_false)

SELECT 
    id, 
    name, 
    IF(score > 60, 'Pass', 'Fail') AS result 
FROM 
    students;

SELECT 
    id, 
    name, 
    IF(score > 60, 'Pass', 'Fail') AS result, 
    IF(score > 90, 'Excellent', IF(score > 70, 'Good', 'Average')) AS grade 
FROM 
    students;

SELECT 
    id, 
    name, 
    CASE 
        WHEN score > 60 THEN 'Pass' 
        ELSE 'Fail' 
    END AS result, 
    CASE 
        WHEN score > 90 THEN 'Excellent' 
        WHEN score > 70 THEN 'Good' 
        ELSE 'Average' 
    END AS grade 
FROM 
    students;

SELECT 
    id, 
    name, 
    CASE 
        WHEN score > 60 THEN 'Pass' 
        ELSE 'Fail' 
    END AS result, 
    CASE 
        WHEN score > 90 THEN 'Excellent' 
        WHEN score > 70 THEN 'Good' 
        ELSE 'Average' 
    END AS grade 
FROM 
    students;