Golang Mongodb collection members starts with a string query-CodePudding

Mongodb collection has a array type and members are string. I want to get if a member of array starts with "abc". How can I write a filter for that?

collection example:

{
_id:"1",
name:"",
data:["abcdfd","gfgqqdg","abcfdgsfg"]
},
{
_id:"2",
name:"",
data:["abcdfd","gfgqqdg","ghfdgsfg"]
},
{
_id:"3",
name:"",
data:["hjhfdfd","gfgqqdg","afdgsfg"]
}

So, find query must return first and second because the "data" has members start with "abc".

CodePudding user response：

You can try using $regex as shown below:

db.collection.find({
  "data": {
    "$regex": "/^abc*/"
  }
})

Also checkout: How to write mongodb query for regex in GoLang using bson?

CodePudding user response：

In MongoDB, you can match any element in array of data using the following syntax:

db.collection.find({ "data": "abcdfd" })

To find documents where any of the array values starts a string "abc", you can use any of the queries:

db.collection.find({ "data": "^abc" })
db.collection.find({ data: { $regex: "^abc" }})
db.collection.find({ data: { $regex: /^abc/ }})

Where, ^ (caret) is a special character used with regular expressions; matches the starting position of a string.

The Golang version of the query:

var results []bson.M
filter := bson.D{{ "data", bson.D{{ "$regex", "^abc" }}}}
cur, err := collection.Find(context.TODO(), filter)

if err != nil {
    log.Fatal(err)
}

if err = cur.All(context.TODO(), &results); err != nil {
    log.Fatal(err)
}
for _, result := range results {
    fmt.Println(result)
}