Update app.py

app.py

@@ -113,10 +113,10 @@ def search_chats_by_date(startDate: str = None, endDate: str = None, maxResults:
         WHERE metadata->>'documentType' = 'chatAnalysis'
     """
     params = []
-    if startDate:
+    if startDate not in (None, ""):
         query += " AND (metadata->>'startTime')::timestamp >= %s"
         params.append(startDate)
-    if endDate:
+    if endDate not in (None, ""):
         query += " AND (metadata->>'startTime')::timestamp < %s"
         params.append(endDate)
     query += " LIMIT %s"