The recommendation of query for find document in viscose don't work

Tony_Cheng · 2022-07-20T13:27:13.998Z

Hi everyone, Thanks for reading this issue.

The query for querying document in the Vscode’s playground is as below

Read One Document

To read one document, use the following syntax in your Playground:

db.collection.findOne(
   { <query> },
   { <projection> }
)

here

But I tried it on the Vsode with no response.

image2830×1590 272 KB

However, when I clicked the choice “Search For Documents” on the left, the coming up query works well


// The current database to use.
use('poem');

// Search for documents in the current collection.
db.getCollection('chinese')
  .find(
    {
      /*
      * Filter
      * fieldA: value or expression
      */
    },
    {
      /*
      * Projection
      * _id: 0, // exclude _id
      * fieldA: 1 // include field
      */
    }
  )
  .sort({
    /*
    * fieldA: 1 // ascending
    * fieldB: -1 // descending
    */
  });

Did I make any mistake(｡ ́︿ ̀｡)? Thanks.

steevej · 2022-07-20T14:12:08.526Z

Most likely you do not have a document with id:1 in the collection chinese of the database poem.

Please share the documents you get when

Tony_Cheng:

clicked the choice “Search For Documents” on the left, the coming up query works well

Tony_Cheng · 2022-07-20T14:52:20.839Z

Thanks for your reply. ^ ^

I just query the document successfully.

Seems caused by syntax error. When I typed use('poem'); instead of use poem;. The query works fine.

Sorry for this. I should’ve be more careful when reading document.

steevej · 2022-07-20T16:57:09.726Z

Tony_Cheng:

Seems caused by syntax error.

You did not mentioned syntax error in the first post, but indicated that you did not get any results. Your screenshot also indicate no result rather than syntax error. As far as I know, at least for mongosh, use Database and use( ‘Database’ ) both produces the same result:

Atlas rent-shard-0 [primary] test> db.chinese.find() 
/* no output */
Atlas rent-shard-0 [primary] test> use poem
switched to db poem
Atlas rent-shard-0 [primary] poem> db.chinese.find()
[ { _id: ObjectId("62d831294569ddb647f8d87e"), x: 369 } ]
Atlas rent-shard-0 [primary] poem> use test
switched to db test
Atlas rent-shard-0 [primary] test> db.chinese.find()
/* no output */
Atlas rent-shard-0 [primary] test> use( 'poem' )
switched to db poem
Atlas rent-shard-0 [primary] poem> db.chinese.find()
[ { _id: ObjectId("62d831294569ddb647f8d87e"), x: 369 } ]

I still think that

steevej:

you do not have a document with id:1 in the collection chinese of the database poem .

Please post a screenshot with

use( 'poem' ) ;
db.chinese.find( { "id" : 1 } ) ;

and

use poem ;
db.chinese.find() ;