LINQ Query string.join

Hi,

I have a list having the bellow.

ID    Flag1   Flag2   Flag3

--------------------------

1      Y         N       N

2      Y         Y       N

3      Y        Y       Y

and I want the result which will be a string which will join all 4 columns and display me result like this format

1,Y,N,N;2,Y,Y,N;3,Y,Y,Y

Thanks in advance!