## **创建一个复合索引** > db.accountsWithIndex.createIndex(**{**name:1,balance:-1}) > 创建一个name值为正序 balance 为倒叙排列的索引 1为从小到大 -1为从大到下 > ## **数据返回 ## ** { "v" : 2, "key" : { "_id" : 1 }, "name" : "_id_" }, { "v" : 2, "key" : { "name" : 1 }, "name" : "name_1" }, { "v" : 2, "key" : { "name" : 1, "balance" : -1 }, "name" : "name_1_balance_-1" } ] }