The best practice is to avoid using the DELETE statement on a queue table because the operation requires a full table scan to rebuild the internal queue table cache. You should reserve this statement for exception handling.
A DELETE statement cannot be specified in a multistatement request that contains a SELECT and CONSUME request for the same queue table.
For details on queue tables and the queue table internal cache, see Teradata Vantage™ - SQL Data Definition Language Detailed Topics, B035-1184.