mongodb查询只显示指定字段

db.COMMODITY_COMMODITY.find(
        {
            "areaCode" : "320100" ,
            "backCatalogId" : { "$in" : [ 111111, 22222]} ,
            "typeCode" : { "$in" : [ "appointment" , "groupon"]} ,
            "status" : "1" ,
            "name" : { "$regex" : "汽车"}
        },{"backCatalogId":true,"_id":0}
)