Sorting a table in lua

[McGuffin]

Hi, i am trying to figure how to sort a table with multiple entries

Here is my problem.
I have something like that

tArray["name1"] = { param1 = 10, params2 = 20, param3 = 50}
tArray["name2"] = { param1 = 5, params2 = 45, param3 = 132}
tArray["name3"] = { param1 = 8, params2 = 55, param3 = 10}

now i want to sort tArray, by using the param1 order.
so i tried somthing like that

function sortParam1(a,b)
   return a[1]<b[1]
end

table.sort(tarray, sortParam1)

but that doesnt work...
is everyone know a way to do this?