should be it

external/duckdb/test/sql/function/uuid/test_uuid.test

@@ -0,0 +1,74 @@
+# name: test/sql/function/uuid/test_uuid.test
+# description: Test gen_random_uuid function
+# group: [uuid]
+
+statement ok
+BEGIN TRANSACTION
+
+statement ok
+CREATE TEMPORARY TABLE t1 AS SELECT gen_random_uuid() a FROM range(0, 16);
+
+statement ok
+CREATE TEMPORARY TABLE t2 AS SELECT uuid() b FROM range(0, 16);
+
+statement ok
+CREATE TEMPORARY TABLE t3 AS SELECT gen_random_uuid() c FROM range(0, 16);
+
+# empty result on this join
+query I
+SELECT COUNT(*) FROM (SELECT a FROM t1 JOIN t2 ON (a=b) JOIN t3 ON (b=c)) s1
+----
+0
+
+statement ok
+ROLLBACK
+
+# use gen_random_uuid in some complicated expressions
+statement ok
+CREATE TABLE uuids(u UUID NOT NULL DEFAULT gen_random_uuid(), a INTEGER);
+
+statement ok
+INSERT INTO uuids (a) VALUES (1), (2), (3), (4), (5), (6), (7), (8), (9), (10);
+
+query I
+SELECT COUNT(DISTINCT u) FROM uuids;
+----
+10
+
+# we can order by gen_random_uuid
+statement ok
+SELECT * FROM uuids ORDER BY gen_random_uuid();
+
+# we can select gen_random_uuid, uuidv4, uuidv7
+statement ok
+SELECT gen_random_uuid() FROM uuids;
+SELECT uuidv4() FROM uuids;
+SELECT uuidv7() FROM uuids;
+
+
+# UUID v4 follows `XXXXXXXX-XXXX-4XXX-XXXX-XXXXXXXXXXXX` format
+query I
+SELECT DISTINCT substring(uuid()::varchar, 15, 1) FROM range(100);
+----
+4
+
+query I
+SELECT DISTINCT substring(uuidv4()::varchar, 15, 1) FROM range(100);
+----
+4
+
+# UUID v7 follows `XXXXXXXX-XXXX-7XXX-XXXX-XXXXXXXXXXXX` format
+query I
+SELECT DISTINCT substring(uuidv7()::varchar, 15, 1) FROM range(100);
+----
+7
+
+# UUID v4 variant 1 follows `XXXXXXXX-XXXX-4XXX-[89ab]XXX-XXXXXXXXXXXX` format
+# the probability for 100 iters not to cover the 4 possible values is (3/4)**100 == 3e-13
+query I
+SELECT DISTINCT substring(uuid()::varchar, 20, 1) AS x FROM range(100) ORDER BY x
+----
+8
+9
+a
+b