diff --git a/Orange/data/sql/backend/postgres.py b/Orange/data/sql/backend/postgres.py
index 25bd945ee3a..936835ad8ff 100644
--- a/Orange/data/sql/backend/postgres.py
+++ b/Orange/data/sql/backend/postgres.py
@@ -4,7 +4,7 @@
 from contextlib import contextmanager
 from time import time
 
-from psycopg2 import Error  # pylint: disable=import-error
+from psycopg2 import Error, ProgrammingError  # pylint: disable=import-error
 from psycopg2.pool import ThreadedConnectionPool  # pylint: disable=import-error
 
 from Orange.data import ContinuousVariable, DiscreteVariable, StringVariable, TimeVariable
@@ -81,7 +81,7 @@ def execute_sql_query(self, query, params=None):
             cur.execute(query, params)
             yield cur
             log.info("%.2f ms: %s", 1000 * (time() - t), utfquery)
-        except Error as ex:
+        except (Error, ProgrammingError) as ex:
             raise BackendError(str(ex)) from ex
         finally:
             connection.commit()
diff --git a/Orange/widgets/data/owsql.py b/Orange/widgets/data/owsql.py
index 63496d4ce55..86e84cce198 100644
--- a/Orange/widgets/data/owsql.py
+++ b/Orange/widgets/data/owsql.py
@@ -214,7 +214,6 @@ def get_table(self):
             what = self.sql = self.sqltext.toPlainText()
             self.table = "Custom SQL"
             if self.materialize:
-                import psycopg2  # pylint: disable=import-error
                 if not self.materialize_table_name:
                     self.Error.connection(
                         "Specify a table name to materialize the query")
@@ -229,7 +228,7 @@ def get_table(self):
                         pass
                     with self.backend.execute_sql_query("ANALYZE " + self.materialize_table_name):
                         pass
-                except (psycopg2.ProgrammingError, BackendError) as ex:
+                except BackendError as ex:
                     self.Error.connection(str(ex))
                     return None