check in clickhouse migration script

db/clickhouse/migrations/02_add_visit_id.sql

@@ -0,0 +1,71 @@
+-- create new table
+CREATE TABLE test.website_event_new
+(
+    website_id UUID,
+    session_id UUID,
+    visit_id UUID,
+    event_id UUID,
+    hostname LowCardinality(String),
+    browser LowCardinality(String),
+    os LowCardinality(String),
+    device LowCardinality(String),
+    screen LowCardinality(String),
+    language LowCardinality(String),
+    country LowCardinality(String),
+    subdivision1 LowCardinality(String),
+    subdivision2 LowCardinality(String),
+    city String,
+    url_path String,
+    url_query String,
+    referrer_path String,
+    referrer_query String,
+    referrer_domain String,
+    page_title String,
+    event_type UInt32,
+    event_name String,
+    created_at DateTime('UTC'),
+    job_id UUID
+)
+    engine = MergeTree
+        ORDER BY (website_id, session_id, created_at)
+        SETTINGS index_granularity = 8192;
+
+INSERT INTO test.website_event_new
+SELECT we.website_id,
+    we.session_id,
+    we2.visit_id,
+    we.event_id,
+    we.hostname,
+    we.browser,
+    we.os,
+    we.device,
+    we.screen,
+    we.language,
+    we.country,
+    we.subdivision1,
+    we.subdivision2,
+    we.city,
+    we.url_path,
+    we.url_query,
+    we.referrer_path,
+    we.referrer_query,
+    we.referrer_domain,
+    we.page_title,
+    we.event_type,
+    we.event_name,
+    we.created_at,
+    we.job_id
+FROM test.website_event we
+JOIN (SELECT DISTINCT
+    s.session_id,
+    generateUUIDv4() visit_id,
+    s.created_at
+FROM (SELECT DISTINCT session_id,
+        date_trunc('hour', created_at) created_at
+    FROM test.website_event) s) we2
+    ON we.session_id = we2.session_id
+        and date_trunc('hour', we.created_at) = we2.created_at
+ORDER BY we.session_id, we.created_at
+
+RENAME TABLE test.website_event TO test.website_event_old;
+RENAME TABLE test.website_event_new TO test.website_event;