match closest number value elasticsearchDSL(php)

Question

I'm having trouble finding an answer on SO, elastic search docs, or google to find this answer for my use case: Find the closest number to X input that is still lower then X.

I have a mapping that looks like this:

{
    "rule": {
        "properties": {
        "price": { "type": "long" }, 
        "from": { "type": "long" }
        }
    }
}

What I need the closest matching from, that is less then the input value. So for example I have these rules:

{
    { "rule": {"from": 1, "price": 5} },
    { "rule": {"from": 50, "price": 4} },
    { "rule": {"from": 100, "price": 3} },
    { "rule": {"from": 150, "price": 2} }
}

If I search for the from with the value off 75, I'd want the rule for "from": 50.

Most of the answers I found were relating to geo/ip or text, I could not find an example that made it click for me.

Answer 1

Range query can be used to get all rules which are less than equal to input value. Top 1 sorted document(by from ) can be returned

Query:

{
  "query": {
    "range": {
      "rule.from": {
        "lte": 75
      }
    }
  },
  "size": 1,
  "sort": [
    {
      "rule.from": {
        "order": "desc"
      }
    }
  ]
}