Handle Optional field search in Elasticsearch - elasticsearch

Question

I am new to query for elasticsearch. I have the problem which took me so long to do research and implement it.
I have 4 fields for searching but not all fields has to be chosen when do searching, some field can leave blank.
For example, employee first name, employee last name, job title and department. I would perform searching such use case: just put first name and last name to get all people have that first and last name, or I can choose last name + first name + job title, or I can choose last name and department only and other params leave blank.
Anyone has an idea for the query. I would appreciate any suggestion.
Thank you

Answer 1

One way to achieve your use case is to use bool query or query_string
Adding a working example with index data, mapping, search query and search result
Index Mapping:
{
"mappings": {
"properties": {
"department": {
"type": "text"
},
"fname": {
"type": "text"
},
"lname": {
"type": "text"
},
"title": {
"type": "text"
}
}
}
}
Index data:
{
"fname": "john",
"title": "faculty",
"department": "navy"
}
{
"fname": "smith",
"title": "faculty",
"department": "navy"
}
{
"fname": "Will",
"lname": "Smith",
"title": "Student",
"department": "engineering"
}
Search Query using bool query:
{
"query": {
"bool": {
"must": [
{
"match": {
"fname": "Smith"
}
},
{
"match": {
"title": "faculty"
}
},
{
"match": {
"department": "navy"
}
}
]
}
}
}
Search Result will be
"hits": [
{
"_index": "67550433",
"_type": "_doc",
"_id": "2",
"_score": 1.9208363,
"_source": {
"fname": "Smith",
"title": "faculty",
"department": "navy"
}
}
]
OR you can even use query_string
{
"query":{
"query_string":{
"query":"fname:smith AND title:faculty AND department:navy"
}
}
}

Answer 2

You can build your query programmatically, as a key-value hash with a 'must' key, and by looping through your input field types, add your fields to the 'must' only if provided.
Alternatively, you can put all the fields under a 'should', assuming that no match will be found for the blank values and therefore there will be no impact on the score and results.