should be it

external/duckdb/benchmark/ldbc/queries/bi-2.sql

@@ -0,0 +1,28 @@
+/* Q2. Tag evolution
+\set year 2010
+\set month 11
+ */
+WITH detail AS (
+SELECT t.t_name
+     , count(DISTINCT CASE WHEN extract(MONTH FROM m.m_creationdate)  = 11 THEN m.m_messageid ELSE NULL END) AS countMonth1
+     , count(DISTINCT CASE WHEN extract(MONTH FROM m.m_creationdate) != 11 THEN m.m_messageid ELSE NULL END) AS countMonth2
+  FROM message m
+     , message_tag mt
+     , tag t
+ WHERE 1=1
+    -- join
+   AND m.m_messageid = mt.mt_messageid
+   AND mt.mt_tagid = t.t_tagid
+    -- filter
+   AND m.m_creationdate >= '2010-11-1'::date
+   AND m.m_creationdate <  '2010-11-1'::date + interval '2' month
+ GROUP BY t.t_name
+)
+SELECT t_name as "tag.name"
+     , countMonth1
+     , countMonth2
+     , abs(countMonth1-countMonth2) AS diff
+  FROM detail d
+ ORDER BY diff desc, t_name
+ LIMIT 100
+;