Case insensitive search in Mongo

Question

I am using a case insensitive search in Mongo, something similar to https://stackoverflow.com/q/5500823/1028488.

ie I am using a regex with options i. But I am having trouble restricting the regex to just that word, it performs more like a 'Like' in SQL

eg: if I use query like {"SearchWord" : { '$regex' : 'win', $options: '-i' }}, it shows me results for win, window & winter. How do i restrict it to jsut show win?

I tried /^win$/ but it's saying invalid JSON... Please suggest away.

Thanks in advance

Solution 1

You can use '$regex':'^win$' or /^win$/i (notice no quote on the second one)

Source here : Regex in queries with Mongo

Solution 2

You can Use $options => i for case insensitive search. Giving some possible examples required for string match.

Exact case insensitive string

db.collection.find({name:{'$regex' : '^string$', '$options' : 'i'}})

Contains string

db.collection.find({name:{'$regex' : 'string', '$options' : 'i'}})

Start with string

db.collection.find({name:{'$regex' : '^string', '$options' : 'i'}})

End with string

db.collection.find({name:{'$regex' : 'string$', '$options' : 'i'}})

Doesn't Contains string

db.collection.find({name:{'$regex' : '^((?!string).)*$', '$options' : 'i'}})

Keep this as a bookmark, and a reference for any other alterations you may need. http://www.cheatography.com/davechild/cheat-sheets/regular-expressions/

Solution 3

UPDATE: As of MongoDB 2.4 one would use a "text" index and full text search query to do this. You can read about them here. If using a recent MongoDB the approach below would be silly and unecessary.

However, if you have MongoDB < 2.4.0 you could use a regular expression like so:

> db.reg.insert({searchword: "win"})
> db.reg.insert({searchword: "window"})
> db.reg.insert({searchword: "Win"})

> db.reg.find()
{ "_id" : ObjectId("4ecd2e33dd68c9021e453d12"), "searchword" : "win" }
{ "_id" : ObjectId("4ecd2e36dd68c9021e453d13"), "searchword" : "window" }
{ "_id" : ObjectId("4ecd2e39dd68c9021e453d14"), "searchword" : "Win" }

> db.reg.find({ searchword: /^win$/i })
{ "_id" : ObjectId("4ecd2e33dd68c9021e453d12"), "searchword" : "win" }
{ "_id" : ObjectId("4ecd2e39dd68c9021e453d14"), "searchword" : "Win" }

However, your version wasn't working because you don't need the "/"s when using the $regex operator:

> db.reg.find({ searchword: { $regex: "^win$", $options: '-i' }})
{ "_id" : ObjectId("4ecd2e33dd68c9021e453d12"), "searchword" : "win" }
{ "_id" : ObjectId("4ecd2e39dd68c9021e453d14"), "searchword" : "Win" }

Please note that case insensitive queries do not use the index so it might make sense to make a lowercase searchword field so that you can speed that query up.

Go here for more info on RegularExpressions

Solution 4

{
          $match: {
            $expr: {
              $and: [
                { $eq: ["$_id", "$$itemId"] },
                {
                  $regexMatch: {
                    input: "$brandData.name",
                    regex: "sample",
                    options: "i",
                  },
                },
              ],
            },
          },
        },

View more solutions

Comments

[B T]

$text isn't a replacement for regex. It is pretty restrictive and wouldn't allow him to find "winter" with a search for "win".

[Rohmer]

@BT You're right. In order to do that one would have to store n-grams and match on those. Fuzzy search with MongoDB and Python

[Rohmer]

Also: Case Insensitive Indexes

[gauravparmar]

By mistake, you had put the example of "Contains string" inside "Exact case insensitive string" and vice-versa. I have edited your answer by swapping the examples for those two cases and also corrected some grammatical mistakes.

[Somnath Muluk]

@gauravparmar: Please check and correct if anything is incorrect.

[gauravparmar]

I have edited your answer but it has to be peer-reviewed, it says.