Example: Creating a Procedure that Consumes a Queue Table - Teradata VantageCloud Lake

The following procedure consumes a shopping cart queue table row that returns the three variables sp_ordernum, sp_product, and sp_quantity:

    CREATE PROCEDURE consumecart(OUT sp_ordernum CHARACTER(15), 
                        OUT sp_product  CHARACTER(30), 
                                 OUT sp_quantity INTEGER) 
    BEGIN 
    SELECT AND CONSUME TOP 1 ordernum, product, quantity INTO 
     :sp_ordernum, :sp_product, :sp_quantity FROM shoppingcart;
    END;

The system retrieves the queue table row at the top of the FIFO queue from a single AMP and deletes the row from the shoppingcart table.

The row was consumed first because its QITS value was the oldest of all rows in the queue. The system builds the response row as specified in the expression list and returns the response row to the requestor in variables.