diff --git a/macros/base_select.sql b/macros/base_select.sql
index 8320b328..ecd4597d 100644
--- a/macros/base_select.sql
+++ b/macros/base_select.sql
@@ -141,7 +141,7 @@
     ) items
     , property_id
     , {{ ga4.unnest_key('event_params', 'ga_session_id', 'int_value', 'session_id') }}
-    , CAST(REGEXP_EXTRACT({{ ga4.unnest_key('event_params', 'ga_session_id', 'string_value', 'session_id_string') }}, r'^GS\d\.\d\.(\d+)') AS INT64) as fallback_session_id
+    , CAST(REGEXP_EXTRACT(COALESCE({{ ga4.unnest_key('event_params', 'ga_session_id', 'string_value', 'session_id_string') }}, ""), r'^GS\d\.\d\.(\d+)') AS INT64) as fallback_session_id
     , {{ ga4.unnest_key('event_params', 'page_location') }}
     , {{ ga4.unnest_key('event_params', 'ga_session_number',  'int_value', 'session_number') }}
     , COALESCE(