Update collector.mssql.md

Signed-off-by: Steven Owatemi <isosteven@gmail.com>

docs/collector.mssql.md

@@ -258,10 +258,23 @@ Name | Description | Type | Labels
 `windows_mssql_waitstats_transaction_ownership_waits` | Statistics relevant to processes synchronizing access to transaction | gauge | `mssql_instance`, `item`
 
 ### Example metric
-_This collector does not yet have explained examples, we would appreciate your help adding them!_
 
+Query Full table scans
+
+```
+rate(windows_mssql_accessmethods_full_scans{instance='host:9182'}[$__rate_interval])
+
+```
 ## Useful queries
 
+### Database file size
+This collector retrieves the two values (data file and log file) and sums the total in PromQL to give the Database file size.
+
+```
+windows_mssql_databases_data_files_size_bytes{database='DatabaseName',instance='host:9182'} + windows_mssql_databases_log_files_size_bytes{database='DatabaseName',instance='host:9182'}
+
+```
+
 ### Buffer Cache Hit Ratio
 
 When you read the counter in perfmon you will get the the percentage pages found in the buffer cache. This percentage is calculated internally based on the total number of cache hits divided by the total number of cache lookups over the last few thousand page accesses.
@@ -284,4 +297,18 @@ This principal can be used for following metrics too:
   - locks_count
 
 ## Alerting examples
-_This collector does not yet have alerting examples, we would appreciate your help adding them!_
+
+```
+groups:
+- name: database_alerts
+  rules:
+  - alert: DatabaseSizeExceeded
+    expr: windows_mssql_databases_data_files_size_bytes{database='DatabaseName',instance='host:9182'} + windows_mssql_databases_log_files_size_bytes{database='DatabaseName',instance='host:9182'} > 1e10  # 10 GB in bytes
+    for: 5m  # Trigger the alert if the condition persists for 5 mins
+    labels:
+      severity: critical
+    annotations:
+      summary: "SQl EXpress Database size exceeded 10GB"
+      description: "The database size has grown larger than 10GB. Instance: {{ $labels.instance }}"
+
+```