Elastic search how can I query either multi match or functions - elasticsearch

Question

I have three following parameters that I will pass to run the query, which are;
query - Either a place name, description or empty,
lat - Either latitude of a place or empty,
lon - Either longitude of a place or empty
Based on above parameters, I get to query list of items based on query scores, then calculate the distance between result and lat, lon.
Now, I have the following script to get the items based on query and distance;
{
"query": {
"function_score": {
"query": {
"bool": {
"must": [{
"multi_match" : {
"query": "Lippo",
"fields": [ "name^6", "city^5", "country^4", "position^3", "address_line^2", "description"]
}
}]
}
},
"functions": [
{
"gauss": {
"position": {
"origin": "-6.184652, 106.7518749",
"offset": "2km",
"scale": "10km",
"decay": 0.33
}
}
}
]
}
}
}
But the thing is, if query is empty, there will be no result at all. What I want is, the result is based on either query or distance.
Is there anyway to achieve this? Any suggestion is appreciated.

Answer 1

setting the zero_terms_query option of multi-match to all should allow you to get the results when query is empty.
Example :
{
"query": {
"function_score": {
"query": {
"bool": {
"must": [{
"multi_match" : {
"query": "Lippo",
"fields": [ "name^6", "city^5", "country^4", "position^3", "address_line^2", "description"],
"zero_terms_query" : "all"
}
}]
}
},
"functions": [
{
"gauss": {
"position": {
"origin": "-6.184652, 106.7518749",
"offset": "2km",
"scale": "10km",
"decay": 0.33
}
}
}
]
}
}
}