Expression to get the string from group of possible values

[#1]

Hi, Thanks for the helpful answers.

Instead of concatenating the attr values, we want to display the attr value of the maximum date..

in the given example,

Input

ID, attr, Date          , value

1,  a   , 03/03/2014, 10

1,  b,  , 04/03/2014,  20

Output

ID, attr, Date1, Date2, Variance

1,   b,    10     ,20     , 10

can someone please provide me the expression to do so?

Thanks

[#2]

Yes, Thats what I implemented  i.e. taking all the attribuites in Expressions. and it works like charm..

Thanks for your time..