diff --git a/.changes/unreleased/Fixes-20230808-113928.yaml b/.changes/unreleased/Fixes-20230808-113928.yaml
new file mode 100644
index 000000000..e1ca74ebe
--- /dev/null
+++ b/.changes/unreleased/Fixes-20230808-113928.yaml
@@ -0,0 +1,6 @@
+kind: Fixes
+body: Revert usage of the walrus operator to extend py37 support
+time: 2023-08-08T11:39:28.603598-04:00
+custom:
+  Author: mikealfare
+  Issue: "868"
diff --git a/dbt/adapters/bigquery/column.py b/dbt/adapters/bigquery/column.py
index a5a60cfc0..b1fc8a390 100644
--- a/dbt/adapters/bigquery/column.py
+++ b/dbt/adapters/bigquery/column.py
@@ -227,7 +227,8 @@ def _update_nested_column_data_types(
             else None
         )
 
-        if existing_nested_column_data_type := nested_column_data_types.get(root_column_name):
+        existing_nested_column_data_type = nested_column_data_types.get(root_column_name)
+        if existing_nested_column_data_type:
             assert isinstance(existing_nested_column_data_type, dict)  # keeping mypy happy
             # entry could already exist if this is a parent column -- preserve the parent data type under "_PARENT_DATA_TYPE_KEY"
             existing_nested_column_data_type.update(