Splunk Query to find all the occurrences of a Boolean key value pair in logs over a period of time

Given below is a snippet of splunk event. My requirement is to find all the occurrences of "isOutstanding": true. Here the point to note is that one event may/may not have multiple occurrences. Need to find the total count from multiple events over a period of time.

{
  \"school\": {
    \"schoolId\": \"1\",
    \"schoolName\": \"SchoolX\",
    \"schoolType\": \"private\",
    \"students\": [
      {
        \"id\": \"1\",
        \"isOutstanding\": true,
        
      },
      {
        \"id\": \"2\",
        \"isOutstanding\": false,
        
      },
      {
        \"id\": \"3\",
        \"isOutstanding\": false,
        
      }
    ]
  }
}

The below Splunk query index=myIndex "isOutstanding":true gives the count of events having "isOutstanding": true. But it doesn't consider the count of multiple occurrences in one event. How can I get the count of all the occourences in an event? TIA

Finally got the query for my requirement

index=myindex sourcetype=mysourceType 
| rex max_match=0 "(?<isOutstanding>isOutstanding\\\\\":true)"
|  stats count(isOutstanding) as total