MXS-2442 ':N' accepted as pos. parameter in Oracle mode

query_classifier/qc_sqlite/qc_sqlite.cc

@@ -878,11 +878,20 @@ public:
                         }
                     }
                 }
-                else if (zToken[0] != '?')
+                else
                 {
+                    // '?' is always accepted as a positional parameter.
+                    if (zToken[0] != '?')
+                    {
+                        // If the mode is Oracle then :N is accepted as well.
+                        if (zToken[0] != ':' || this_thread.sql_mode != QC_SQL_MODE_ORACLE)
+                        {
+                            // Everything else is unexpected, but harmless.
                             MXS_WARNING("%s reported as VARIABLE.", zToken);
                         }
                     }
+                }
+            }
             break;
 
         default: