diff --git a/django/db/backends/postgresql/base.py b/django/db/backends/postgresql/base.py
index 1aeaa8b437..89695b0c4b 100644
--- a/django/db/backends/postgresql/base.py
+++ b/django/db/backends/postgresql/base.py
@@ -170,7 +170,7 @@ def get_sql_flush(style, tables, sequences):
             # single SQL TRUNCATE statement.
             sql = ['%s %s;' % \
                 (style.SQL_KEYWORD('TRUNCATE'),
-                 style.SQL_FIELD(', '.join(quote_name(table) for table in tables))
+                 style.SQL_FIELD(', '.join([quote_name(table) for table in tables]))
             )]
         else:
             # Older versions of Postgres can't do TRUNCATE in a single call, so they must use 
diff --git a/django/db/backends/postgresql_psycopg2/base.py b/django/db/backends/postgresql_psycopg2/base.py
index 46ae67779d..9b319ad3c7 100644
--- a/django/db/backends/postgresql_psycopg2/base.py
+++ b/django/db/backends/postgresql_psycopg2/base.py
@@ -129,7 +129,7 @@ def get_sql_flush(style, tables, sequences):
             # single SQL TRUNCATE statement
             sql = ['%s %s;' % \
                     (style.SQL_KEYWORD('TRUNCATE'),
-                     style.SQL_FIELD(', '.join(quote_name(table) for table in tables))
+                     style.SQL_FIELD(', '.join([quote_name(table) for table in tables]))
                     )]
         else:
             sql = ['%s %s %s;' % \