CODEWITHSUNDEEP
mongodbgo
Apin
Apin

Reputation: 2668

Golang MongoDB Driver sort

How to query find using golang mongodb driver?

I try this one :

db.Collection("products").Find(nil, bson.M{}, &options.FindOptions{Sort: "-price"})

But I got this error :

cannot transform type string to a BSON Document: WriteString can only write while positioned on a Element or Value but is positioned on a TopLevel

I don't know what to pass to Sort variable becuase it is an interface{}.

Upvotes: 16

Views: 29602

Answers (6)

Younesious
Younesious

Reputation: 21

Another point that I came across by the Vim IDE that I use. It was for this line:

findOptions := options.Find()
// Sort by `price` field descending
findOptions.SetSort(bson.D{{"price", -1}})


db.Collection("products").Find(nil, bson.D{}, findOptions)

I got: "go.mongodb.org/mongo-driver/bson/primitive.E struct literal uses unkeyed fields" warning,(I know that many people do not care about it :ـ) Because In Go, bson.D is a slice of bson.E, and bson.E should use keyed fields for proper initialization. then you can simply put Key and Value to resolve that:

findOptions := options.Find()
// Sort by `price` field descending
findOptions.SetSort(bson.D{{Key: "price",Value: -1}})


db.Collection("products").Find(nil, bson.D{}, findOptions)

Upvotes: 1

Binwin Viju
Binwin Viju

Reputation: 334

Try this method

findOptions := options.Find()
// Sort by `price` field descending
findOptions.SetSort(bson.M{"price": -1})


db.Collection("products").Find(nil, bson.D{}, findOptions)

This helped me to fix my code.This problem is due to the version of go that you are using.

Upvotes: 0

gsmig
gsmig

Reputation: 100

Another point to note, make sure that mapping of field names are correct. In my case i was trying to sort a field createdAt but after realized my mongodb field is mapped as createdat.

queryOptions.SetSort(bson.D{{"createdat", -1}

Upvotes: 0

Amin Shojaei
Amin Shojaei

Reputation: 6528

I couldn't pass ‍‍bson.D to options(It caused error). but this code worked for me:

    queryOptions := options.FindOneOptions{}
    
    queryOptions.SetSort(bson.D{{"priority", -1}, {"last_error_time", 1}})

    sResult := collection.FindOne(context.TODO(), queryFilter, &queryOptions)

Upvotes: 8

Matt
Matt

Reputation: 91

A few notes I've come across trying to solve a related problem:

  • If trying to sort by multiple fields be sure to use bson.D rather than bson.M because bson.M doesn't preserve order.

  • If trying to programmatically build up multiple sort fields, try
    appending bson.E to a bson.D

  • As dassum did, pass bson.M{} for an empty filter as recommended by
    the mongo documentation

Applied:

sort := bson.D{}
for _, example := examples {
    sort = append(sort, bson.E{example, 1})
}

findOptions.SetSort(sort)
db.Collection("products").Find(nil, bson.D{}, findOptions)

Upvotes: 4

dassum
dassum

Reputation: 5103

try the below code

findOptions := options.Find()
// Sort by `price` field descending
findOptions.SetSort(bson.D{{"price", -1}})


db.Collection("products").Find(nil, bson.D{}, findOptions)

Upvotes: 38

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