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Legal StudiesMongoDB 查詢使用 $pull / $unset 與多個條件？
為此，請與 update 一同使用 $pull。我們建立一個包含文件的集合 -
> db.demo198.insertOne({"List":{"Values":[10,20,30,30,70,80,90]}});
{
"acknowledged" : true,
"insertedId" : ObjectId("5e3c224503d395bdc21346df")
}
> db.demo198.insertOne({"List":{"Values":[56,978,56,34,23,34]}});
{
"acknowledged" : true,
"insertedId" : ObjectId("5e3c225403d395bdc21346e0")
}
> db.demo198.insertOne({"List":{"Values":[21,12,14,15,34,56]}});
{
"acknowledged" : true,
"insertedId" : ObjectId("5e3c226603d395bdc21346e1")
}在集合中使用 find() 方法顯示所有文件 -
> db.demo198.find();
這將生成以下輸出 -
{ "_id" : ObjectId("5e3c224503d395bdc21346df"), "List" : { "Values" : [ 10, 20, 30, 30, 70, 80, 90 ] } }
{ "_id" : ObjectId("5e3c225403d395bdc21346e0"), "List" : { "Values" : [ 56, 978, 56, 34, 23, 34 ] } }
{ "_id" : ObjectId("5e3c226603d395bdc21346e1"), "List" : { "Values" : [ 21, 12, 14, 15, 34, 56 ] } }以下是使用 $pull / $unset 與多個條件的查詢 -
> db.demo198.update({},{ "$pull": { "List.Values": { "$lt": 40 } } },{ "multi": true });
WriteResult({ "nMatched" : 3, "nUpserted" : 0, "nModified" : 3 })在集合中使用 find() 方法顯示所有文件 -
> db.demo198.find();
這將生成以下輸出 -
{ "_id" : ObjectId("5e3c224503d395bdc21346df"), "List" : { "Values" : [ 70, 80, 90 ] } }
{ "_id" : ObjectId("5e3c225403d395bdc21346e0"), "List" : { "Values" : [ 56, 978, 56 ] } }
{ "_id" : ObjectId("5e3c226603d395bdc21346e1"), "List" : { "Values" : [ 56 ] } }
更新日期： 2020-03-27
295 次瀏覽
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