opentelemetry-instrumentation-sqlalchemy: Fix exception on empty query

Author: plentydone

CHANGELOG.md

@@ -13,6 +13,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Fixed
 
+- `opentelemetry-instrumentation-sqlalchemy`: Fix exception on empty query
+  ([#3860](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/3860))
 - `opentelemetry-instrumentation-botocore`: migrate off the deprecated events API to use the logs API
   ([#3624](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/3624))
 - `opentelemetry-instrumentation-dbapi`: fix crash retrieving libpq version when enabling commenter with psycopg

instrumentation/opentelemetry-instrumentation-sqlalchemy/src/opentelemetry/instrumentation/sqlalchemy/engine.py

@@ -239,9 +239,11 @@ def _operation_name(self, db_name, statement):
             # For some very special cases it might not record the correct statement if the SQL
             # dialect is too weird but in any case it shouldn't break anything.
             # Strip leading comments so we get the operation name.
-            parts.append(
-                self._leading_comment_remover.sub("", statement).split()[0]
-            )
+            split_query = self._leading_comment_remover.sub(
+                "", statement
+            ).split()
+            if split_query:
+                parts.append(split_query[0])
         if db_name:
             parts.append(db_name)
         if not parts: