Use Artifactory JFrog CLI to delete all *-SNAPSHOT builds but always ensure to leave one behind

Question

I have been using Artifactory JFrog cli & AQL lanaguage to cleanup maven SNAPSHOT builds. So far I have been deleting everything by pattern matching *-SNAPSHOT. However I wish to have 1 build (the youngest) remain, as these are required for other builds. Would anyone be able to point me in the right direction, as I cant find anything obvious in Artifactorys docs.

My current query looks like the following

{
  "files": [
    {
      "aql": {
        "items.find": {
          "repo": "test-repo",
          "path": {"$match":"root-folder/*"},
          "name": {"$match":"*-SNAPSHOT"},
          "type": "folder",
          "$or": [
            {
              "$and": [
                {
                  "created": { "$before":"7d" }
                }
              ]
            }
          ]
        }
      }
    }
  ]
}

Directory structure looks like the following

test-repo/root-folder/maven-project1/1.7.0-SNAPSHOT/
test-repo/root-folder/maven-project1/1.8.0-SNAPSHOT/
test-repo/root-folder/maven-project2/1.7.0-SNAPSHOT/
test-repo/root-folder/maven-project2/1.8.0-SNAPSHOT/

In this example I would want to keep the latest builds i.e. v1.8.0