[Aetae]

var db=[
  ["A","B"],
  ["B","B"],
  ["B","A"],
  ["A","A"]
]
db.sort(function(a,b){
     if (a[1] < b[1]){
        return -1;
     }else if (a[1] > b[1]) {
        return  1;
     }else{
        return 0;
     }
})
alert(db.join('\n'))