SQL Query Duplicate Removal Help

Question

I need to remove semi duplicate records from the following table

ID      PID      SCORE
1       1        50
2       33       20
3       1        90
4       5             


        

Answer 1

    DELETE t.* 
    FROM Table1 t 
    JOIN (SELECT pid, MIN(score) minScore, MAX(id) maxId
            FROM Table1
        GROUP BY pid) t1 
    ON t.pid = t1.pid 
   AND t.score = t1.minScore 
   AND t.id < t1.maxId