Follow below method -
To Search different things you need to use different input fields otherwise you got to create your custom filter with your type of requirements
<label>Any: <input ng-model="search.$"></label> <br>
<label>Name only <input ng-model="search.name"></label><br>
<label>RollNo only <input ng-model="search.RollNo"></label><br>
<table>
<tr ng-repeat="x in names | filter:search">
<td>{{x.name}}</td>
<td>{{x.RollNo}}</td>
</tr>
</table>
EDIT
Here is custom filter for your case:
.filter('TableFilter', function(){
return function(dataArray, type, filtervalue) {
if (!dataArray) {
return;
}else{
if(type === 'Name'){
return dataArray.filter(function(item){
var term = item.name === filtervalue;
return term;
});
}else if(status === 'RollNo'){
return dataArray.filter(function(item){
var term = item.RollNo === filtervalue;
return term;
});
}
}
}
});
<tr ng-repeat="x in names | TableFilter : dropDownvalue : test">