查詢Mongodb中的子文檔數組

Question

我有一個像這樣的文檔集合：

{
  name: "Whatever 1".
  distances: [
    {name: "first distance", distance: 3000},   
    {name: "another distance", distance: 8000},
  ]
},
{
  name: "Whatever 2".
  distances: []
},
{
  name: "Whatever 3".
  distances: [
    {name: null, distance: 6000},   
  ]
},
{
  name: "Whatever 4".
  distances: [
    {name: "hello", distance: 100000},   
  ]
},

我需要獲取包含給定范圍內距離的所有文檔。

示例：如果我查詢大於5000且小於9000距離，我想獲得文檔"Whatever 1"和"Whatever 3"

我怎樣才能做到這一點？

Answer 1

您可以使用$elemMatch為distances數組的單個子文檔指定范圍條件：

db.col.find({ distances: { $elemMatch: { distance: { $gt: 5000, $lt: 9000 } } } })