Remove a field from all elements in array in mongodb

[Anonymous]

I have document in MongoDB(2.4.5)

I want to remove withBase filed from array elements inside casts.crew ..

I tried this

db.coll.update({_id:235399},{$unset: {  "casts.crew.withBase" : 1 } },false,true)

nothing changed.

And tried this..

db.coll.update({_id:235399},{$unset: {  "casts.crew" : { $elemMatch: { "withBase": 1 } } } },false,true)

it removed entire crew array from the document.

Can someone please provide me the right query?