Azure Cognitive Search: how to correctly search for certain one-char value

Question

In Azure Search I have an index that has a batch of documents. Documents are JSONs and one of the documents has the following fields (abriged):

{
  "id": "1638",
  "segment": "N",
  "segmentIndicator": 1.23,     
}

and some other documents where segment is present, but is null.

I issue a search request using POST, as described under the link. I am getting valid results for id and segmentIndicator using the requests like

{
    "search": "id:(\"1638\")",
    "queryType": "full",
    "searchMode": "all"
}
or
{
    "search": "segmentIndicator:(\"1.23\")",
    "queryType": "full",
    "searchMode": "all"
}

as they both return the desired document and nothing else. I am not able to change queryType and searchMode and an exact match to my search criteria is needed (no fuzzy / proximity search).

However, when I say

{
    "search": "segment:(\"N\")",
    "queryType": "full",
    "searchMode": "all"
}

I am getting an empty search result, while I expect the same document to be found. How I can alter my query so I can correctly find the document by segment parameter?

What analyzer are you using for the segment field, if any? Also, do you need to match on segment even if the case doesn't match (e.g. -- "n" and "N" should both match)? If case-sensitive exact matches are fine, why not use a filter? — Bruce Johnston
@BruceJohnston - I just send this query as is. I am very new to this service so do not know how to see / use analyzers atm. I believe I need exact match, case sensitive. — Askar Ibragimov

Bruce Johnston Bruce Johnston · Accepted Answer · 2020-08-21T02:06:12

While I'm not sure why the single letter doesn't match, I'd speculate that it's probably being treated as a stopword and eliminated during lexical analysis of the query. The search parameter is best used for true full-text search scenarios.

It sounds like what you need is the $filter parameter, which is a strict Boolean predicate that does exact (case-sensitive) matches on field values, including values of all data types (not just strings). You can find a good introduction to filters in Azure Cognitive Search here. The full syntax reference is here.

Here is an example of how to filter on a string field for an exact match with 'N':

segment eq 'N'

Azure Cognitive Search: how to correctly search for certain one-char value

1 Answers