mongodb translation for sql INSERT…SELECT

Question

How to simply duplicate documents from collectionABC and copy them into collectionB if a condition like {conditionB:1} and add a timestamp like ts_imported - without knowing

Answer 1

You can use javascript from mongoshell to achieve a similar result:

db.collectionABC.find({ conditionB: 1 }).
forEach( function(i) { 
  i.ts_imported = new Date();
  db.collectionB.insert(i);
});