Update migration script.

Author: mikecao

scripts/data-migrations/convert-utm-clid-columns.sql

@@ -25,7 +25,8 @@ FROM (SELECT event_id, website_id, session_id,
           (regexp_matches(url_query, '(?:[&?]|^)utm_medium=([^&]+)', 'i'))[1] AS utm_medium,
           (regexp_matches(url_query, '(?:[&?]|^)utm_source=([^&]+)', 'i'))[1] AS utm_source,
           (regexp_matches(url_query, '(?:[&?]|^)utm_term=([^&]+)', 'i'))[1] AS utm_term
-    FROM "website_event") url
+    FROM "website_event"
+    WHERE url_query IS NOT NULL) url
 WHERE we.event_id = url.event_id
     and we.session_id = url.session_id
     and we.website_id = url.website_id;
@@ -45,4 +46,4 @@ SET fbclid = LEFT(SUBSTRING_INDEX(SUBSTRING_INDEX(REGEXP_SUBSTR(url_query, '(?:[
     utm_medium = LEFT(SUBSTRING_INDEX(SUBSTRING_INDEX(REGEXP_SUBSTR(url_query, '(?:[&?]|^)utm_medium=[^&]+'), '=', -1), '&', 1), 255),
     utm_source = LEFT(SUBSTRING_INDEX(SUBSTRING_INDEX(REGEXP_SUBSTR(url_query, '(?:[&?]|^)utm_source=[^&]+'), '=', -1), '&', 1), 255),
     utm_term = LEFT(SUBSTRING_INDEX(SUBSTRING_INDEX(REGEXP_SUBSTR(url_query, '(?:[&?]|^)utm_term=[^&]+'), '=', -1), '&', 1), 255)
-WHERE 1 = 1;
+WHERE url_query IS NOT NULL;