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

try this..

    declare @tt table(id int, pid int,score int)
    insert into @tt
    select 1,1,50 union all
    select 2,33,50 union all
    select 8,33,80 union all
    select 3,1,90 union all
    select 4,5,50 union all
    select 5,5,10 union all
    select 6,6,10 union all
    select 7,6,50  
    ---------   
    delete from @tt where id in (
    select t1.id from @tt t1 inner join
    (
        select  MIN(score) tScore,pid tPid from @tt where pid in 
        (select  pid from @tt group by pid having count (pid) > 1) group by pid 
    ) t2 on t1.pid=t2.tPid and t1.score=t2.tScore)

    select * from @tt