Combine $text with $regex

Working with Data
, ,
#1

Hi everyone,

I would like to obtain the results of a text search with the results of a regex. In particular, assuming that the input string is “substring”, I would like to be able to do the following filter:

{ $or : [ { name : { $regex : “.substring.” } }, {$text : { $search: “substring” } } ] }

Of course, I’ve previously created the $text index on “name” field, however it gives me a Mongo Error since $or and $text operator cannot be used together.
How can I achieve this filtering?

Thanks in advance

#2

Hi @Matteo_Tarantino ,

Why do you need this kind of double search if you already perform a text search. In general we recommend using Atlas search for full text searches if it happens that your cluster is an Atlas cluster:

If you still insist on running this query using the traditional text indexes , I believe the use of $unionWith aggregation might work:

[{$match: {
 $text: {
  $search: 'substring'
 }
}}, {$unionWith: {
 coll: '<COLLECTION-NAME>',
 pipeline: [
  {
   $match: {
    name: {
     $regex: '. substring.'
    }
   }
  }
 ]
}}]

Ty

#3

Hi @Pavel_Duchovny ,

to the best of my knowledge $search operator does not find a match if the searching string is actually a substring of the field I’m seaching on. In particular:

Suppose that you are searching by name and the name field of a document is “Matteo”. If the searching string is “atte” the $search operator discards that document. At leats I’m experiencing this behavior when applying the $search operator in a serverless atlas cluster. Is it correct?

#4

Hi @Matteo_Tarantino ,

Do you mean when using the “regex” operator in the $search stage of Atlas Search?

With regex operator (I linked you with…) you can search for partial expressions of a word:

[{$search: {
 regex: {
  path: 'title',
  query: '.*los.*',
  allowAnalyzedField: true
 }
}}]

In this example I search the sample_mflix.movies collection using a regex .*los.* and it find strings like:

title : "Broken Blossoms or The Yellow Man and the Girl"
...
title : "The Lost World"

Thanks
Pavel