[ddsql] Add examples of multi-valued tags handling to DDSQL tags documentation (#31292)

* Add examples of multi-valued tags handling to DDSQL tags documentation

I'd like to add an example of what happens in DDSQL when a resource has multiple values for the same tag key. This is a potential stumbling-block for customers and I'd like to be sure that it's well-documented in case customers run into this.

* Update codeowners for DDSQL Reference

* Apply PR feedback for future -> present tense

Co-authored-by: Brett Blue <[email protected]>

---------

Co-authored-by: Brett Blue <[email protected]>

Author: mhintz

.github/CODEOWNERS

@@ -165,7 +165,7 @@ content/en/code_analysis/                         @Datadog/static-analysis @Data
 content/en/quality_gates/                         @Datadog/ci-app-backend @Datadog/documentation
 
 # DDSQL Editor References
-content/en/ddsql_reference/*.md                     @Datadog/xpq @Datadog/documentation @Datadog/advanced-query-guild
+content/en/ddsql_reference/*.md                   @Datadog/documentation @Datadog/advanced-query-guild
 
 # Data Streams Monitoring
 content/en/data_streams/*.md                      @Datadog/data-streams-monitoring @Datadog/documentation

content/en/ddsql_reference/_index.md

@@ -677,7 +677,7 @@ ORDER BY value DESC;{{< /code-block >}}
 
 ## Tags
 
-DDSQL exposes tags as an `hstore` type, which you can query using the PostgreSQL arrow operator. For example:
+DDSQL exposes tags as an `hstore` type, which is inspired by PostgreSQL. You can access the values for specific tag keys using the PostgreSQL arrow operator. For example:
 
 ```sql
 SELECT instance_type, count(instance_type)
@@ -686,7 +686,15 @@ WHERE tags->'region' = 'us-east-1' -- region is a tag, not a column
 GROUP BY instance_type
 ```
 
-Tags are key-value pairs where each key can have zero, one, or multiple values. When accessed, the tag value returns a string containing all corresponding values.
+Tags are key-value pairs where each key can have zero, one, or multiple tag values corresponding to it. When accessed, the tag value returns a single string, containing _all_ corresponding values. When the data has multiple tag values for the same tag key, they are represented as a sorted, comma-separated string. For example:
+
+```sql
+SELECT tags->'team', instance_type, architecture, COUNT(*) as instance_count
+FROM aws.ec2_instance
+WHERE tags->'team' = 'compute_provisioning,database_ops'
+GROUP BY tags->'team', instance_type, architecture
+ORDER BY instance_count DESC
+```
 
 You can also compare tag values as strings or entire tag sets: