db.idap_zl.insert({array:[]})
db.idap_zl.insert({array:[1,2,3,4,5]})
db.idap_zl.find({array:{elemMatch:{ne:null}}})
db.Collection.find({array:{$elemMatch:{$ne:null}}})
db.Collection.find({$where:"this.array.length>0"})
db.Collection.find({array: {$not: {$size: 0}}})
db.Collection.find({{'array.0': {$exists: 1}}})
db.Collection.find({ array: { exists: true, ne: [] } })
db.Collection.find({ array: { $gt: [] } })