hi all,
i need help to get the maximum fifty values , for every department as

as

no dept  val
1    1     1000
2    1      990
3    1      800
 .           650
 .           530
50   1      120

1      2     3500
2      2     2800 
.       2      .
.       2      .  
.       2
50     2

1      3

thanks