sorting data in matrix

say i have a matrix

 a = [2 3; 1 3; 3 2; 2 2; 1 2; 3 1; 2 1; 1 1]

i would like to rearrange a such that the first column is sorted in ascending order corresponding to the number in the second column ie. this matrix should become

 asorted = [1 3; 2 3; 1 2; 2 2; 3 2; 1 1; 2 1; 3 1]

how can this be done automatically

Answer 1

[Andrei Bobrov]

asorted = sortrows(a,[-2 1])