mongodb contains in array code example

Example 1: contains mongo-query string

db.users.findOne({"username" : {$regex : ".*son.*"}});

Example 2: mongodb array field contains

db.inventory.find( { tags: ["red", "blank"] } )

Example 3: mongodb array field contains

db.inventory.find( { tags: { $all: ["red", "blank"] } } )

Example 4: find string element in an array mongodb

db.articles.find({
    "stock.country" : "01",
    "stock.warehouse.code" : "02"
}).pretty();