Solr: Query Facet and count missing

Question

In my Solr index I have an optional date field. Let's call it Property_3_1044.

I want to find the maximum and the minimum of Property_3_1044 as well as the number of all items without that date.

I believe faceting is the best approach. Please correct me if there is a better way!

Using Query Facets I can use aggregate functions min and max to obtain minimum and maximum, respectively:

http://localhost:8983/solr/Shard/query?q=:&json.facet={Date1:{type:query,facet:{"min":"min(Property_3_1044)","max":"max(Property_3_1044)"}}}&rows=0

Result:

"facets":{
  "count":249,
  "Date1":{
    "count":249,
    "min":"2019-01-09T00:00:00Z",
    "max":"2019-01-22T00:00:00Z"}}}

(Question aside: How to get rid of the 2 counts?)

Using Terms Facets I can use the missing parameter to find all items without date:

http://localhost:8983/solr/Shard/query?q=:&rows=0&json.facet={Date2:{terms:{field:Property_3_1044,missing:true,limit:0}}}

Result:

"facets":{
  "count":249,
  "Date2":{
    "buckets":[],
    "missing":{
      "count":240}}}}

How can I combine these two queries? I know I can just execute both (by just concatenating the two queries strings), but I'd like to know whether there is a more efficient way. I assume that performing both a query facet and a terms facet is more expensive than just having a single facet. For example, an aggregate function missing would allow me to do everything just using the query facet (but there is no such method, is there?).

Jack Miller Jack Miller · Accepted Answer · 2019-01-25T12:06:30

I found a solution myself; I just need to add a facet query q which filters for not-null values -> [* TO *]:

http://localhost:8983/solr/Shard/query?q=:&json.facet={Date1:{type:query,q:"Property_3_1044:[* TO *]",facet:{"min":"min(Property_3_1044)","max":"max(Property_3_1044)"}}}&rows=0

In the result, the outer count is the number of all items (here: 225) and the inner facet count will give the the number of items with date set, ie. after q was applied (here: 9):

"facets":{
  "count":225,
  "Date1":{
    "count":9,
    "min":"2019-01-09T00:00:00Z",
    "max":"2019-01-22T00:00:00Z"}}}

The number of items without date is the difference (225-9=216).

Solr: Query Facet and count missing

1 Answers