sorting data based on multi columns



hi all

i have data in following format:

csch74,2007,1,09103,15
csch74,2007,10,09103,0
csch74,2007,11,09103,0
csch74,2007,12,09103,0
csch74,2007,2,09103,15
csch74,2007,3,09103,194
csch74,2007,4,09103,115
csch74,2007,5,09103,66
csch74,2007,6,09103,0
csch74,2007,7,09103,0
csch74,2007,8,09103,0
csch74,2007,9,09103,0
cscs74,2007,1,09103,142
cscs74,2007,10,09103,0
cscs74,2007,11,09103,0
cscs74,2007,12,09103,0
cscs74,2007,2,09103,1224
cscs74,2007,3,09103,1332
cscs74,2007,4,09103,1169
cscs74,2007,5,09103,195
cscs74,2007,6,09103,0
cscs74,2007,7,09103,0
cscs74,2007,8,09103,0
cscs74,2007,9,09103,0

i want to sort it so that output is ( basically sort on column1 and 3)

csch74,2007,1,09103,15
csch74,2007,2,09103,15
csch74,2007,3,09103,194
csch74,2007,4,09103,115
csch74,2007,5,09103,66
csch74,2007,6,09103,0
csch74,2007,7,09103,0
csch74,2007,8,09103,0
csch74,2007,9,09103,0
csch74,2007,10,09103,0
csch74,2007,11,09103,0
csch74,2007,12,09103,0
cscs74,2007,1,09103,142
cscs74,2007,2,09103,1224
cscs74,2007,3,09103,1332
cscs74,2007,4,09103,1169
cscs74,2007,5,09103,195
cscs74,2007,6,09103,0
cscs74,2007,7,09103,0
cscs74,2007,8,09103,0
cscs74,2007,9,09103,0
cscs74,2007,10,09103,0
cscs74,2007,11,09103,0
cscs74,2007,12,09103,0

i have tried :

sort -t, +2 -3 +0 -1 file
sort -t, -k3,3 n -k1,1 file
sort -t"," -k3,3 n -k1,1 file

result is not what i wanted

csch74,2007,1,09103,15
cscs74,2007,1,09103,142
cscx74,2007,1,09103,28
csyh74,2007,1,09103,57
csys74,2007,1,09103,165
csyx74,2007,1,09103,11
d13h41,2007,1,08475,5
d13h42,2007,1,08475,43
d13h62,2007,1,08475,1
d13h81,2007,1,08475,12
d13l41,2007,1,08475,0


sort -t, -k1,1 -k3,3 n file
sort -t"," -k1,1 -k3,3 n file
sort -t"," -k 1,1 -k 3,3 n file


for all the above command the output is same as input file with statement cannot open 'n' and in last case cannot open -k 3,3 and n.

sort -t, -k1,1 -k3,3 -n file (comes up with usage of sort command)


nothing seems to work. any help from unix gurus is appreciated.

thanks