diff --git a/doc/operation-class.md b/doc/operation-class.md
index 1d7c08d..e9522a7 100644
--- a/doc/operation-class.md
+++ b/doc/operation-class.md
@@ -27,7 +27,7 @@ class MessageRetentionOperation(BaseOperation):
             INSERT INTO {self.source_db}.{self.destination_table}({self.source_columns})
             SELECT {self.source_columns}
             FROM {self.source_db}.{self.source_table} AS source
-            WHERE source. BETWEEN {start_pk} AND {end_pk}
+            WHERE source.{self.pk_column} BETWEEN {start_pk} AND {end_pk}
             AND source.ts > DATE_SUB(NOW(), INTERVAL 30 DAY)
         """
     def _get_not_imported_pks_query(self, start_pk, end_pk):
diff --git a/src/sbosc/controller/initializer.py b/src/sbosc/controller/initializer.py
index dffbd3b..788051e 100644
--- a/src/sbosc/controller/initializer.py
+++ b/src/sbosc/controller/initializer.py
@@ -186,7 +186,9 @@ def fetch_metadata(self, redis_data):
             self.logger.info("Saved primary key column to Redis")
 
             # Get max id
-            cursor.execute("SELECT MAX(%s) FROM %s.%s" % (metadata.pk_column, metadata.source_db, metadata.source_table))
+            cursor.execute('''
+                SELECT MAX(%s) FROM %s.%s
+            ''' % (metadata.pk_column, metadata.source_db, metadata.source_table))
             max_pk = cursor.fetchone()[0]
             if max_pk is None:
                 raise Exception("No data in source table")
diff --git a/src/sbosc/controller/validator.py b/src/sbosc/controller/validator.py
index ca8cdd5..96b5f78 100644
--- a/src/sbosc/controller/validator.py
+++ b/src/sbosc/controller/validator.py
@@ -153,13 +153,15 @@ def __execute_apply_dml_events_validation_query(
             if event_pks:
                 event_pks_str = ','.join([str(pk) for pk in event_pks])
                 dest_cursor.execute(f'''
-                    SELECT {metadata.pk_column} FROM {metadata.destination_db}.{metadata.destination_table} WHERE {metadata.pk_column} IN ({event_pks_str})
+                    SELECT {metadata.pk_column} FROM {metadata.destination_db}.{metadata.destination_table}
+                    WHERE {metadata.pk_column} IN ({event_pks_str})
                 ''')
                 not_deleted_pks = set([row[0] for row in dest_cursor.fetchall()])
                 if dest_cursor.rowcount > 0:
                     # Check if deleted pks are reinserted
                     source_cursor.execute(f'''
-                        SELECT {metadata.pk_column} FROM {metadata.source_db}.{metadata.source_table} WHERE {metadata.pk_column} IN ({event_pks_str})
+                        SELECT {metadata.pk_column} FROM {metadata.source_db}.{metadata.source_table}
+                        WHERE {metadata.pk_column} IN ({event_pks_str})
                     ''')
                     reinserted_pks = set([row[0] for row in source_cursor.fetchall()])
                     if reinserted_pks:
diff --git a/src/sbosc/operations/base.py b/src/sbosc/operations/base.py
index 66293b3..2eda1a6 100644
--- a/src/sbosc/operations/base.py
+++ b/src/sbosc/operations/base.py
@@ -41,7 +41,8 @@ def apply_update(self, db, updated_pks):
     def _get_not_imported_pks_query(self, start_pk, end_pk):
         return f'''
             SELECT source.{self.pk_column} FROM {self.source_db}.{self.source_table} AS source
-            LEFT JOIN {self.destination_db}.{self.destination_table} AS dest ON source.{self.pk_column} = dest.{self.pk_column}
+            LEFT JOIN {self.destination_db}.{self.destination_table} AS dest
+            ON source.{self.pk_column} = dest.{self.pk_column}
             WHERE source.{self.pk_column} BETWEEN {start_pk} AND {end_pk}
             AND dest.{self.pk_column} IS NULL
         '''