Add Generate Random UUIDs Without An Extension as a postgres til

postgres/generate-random-uuids-without-an-extension.md

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+# Generate Random UUIDs Without An Extension
+
+In other posts I've covered how to generate v4 random UUIDs in PostgreSQL
+[using the `uuid-ossp` extension](generate-a-uuid.md) as well as the more
+up-to-date method of [using the `pgcrypto`
+extension](generating-uuids-with-pgcrypto.md).
+
+As of PostgreSQL v13, you no longer need to add an extension for v4 UUID
+generation. It comes built-in as the `gen_random_uuid()` function.
+
+```sql
+> select gen_random_uuid();
+           gen_random_uuid
+--------------------------------------
+ 0aa72fe6-ede7-4ccf-b328-348becc58066
+(1 row)
+```
+
+If you need other non-v4 UUID functions, you'll have to stick with
+[uuid-ossp](https://www.postgresql.org/docs/current/uuid-ossp.html).