如何在Teradata中创建虚拟列？

Question

是否可以在Teradata中创建虚拟列，即基于同一个表的其他列的值的列，例如：

CREATE SET TABLE TEST.ZZ_RECEIPTS,
    NO FALLBACK ,
    NO BEFORE JOURNAL,
    NO AFTER JOURNAL,
    CHECKSUM = DEFAULT,
    DEFAULT MERGEBLOCKRATIO
(
    ID_RECEIPT NUMBER,
    ID_ITEM NUMBER,
    NUM_ITEM NUMBER,
    VALUE_ITEM DECIMAL (10, 2)
/*,
    -- TOTAL_ITEM is the virtual column I want to add 
    TOTAL_ITEM DECIMAL (10, 2) AS (NUM_ITEM * VALUE_ITEM)
*/
) PRIMARY INDEX (ID_RECEIPT, ID_ITEM);

INSERT INTO TEST.ZZ_RECEIPTS (ID_RECEIPT, ID_ITEM, NUM_ITEM, VALUE_ITEM) VALUES (1, 1, 3, 4.50); --3*4,50 = 13,50
INSERT INTO TEST.ZZ_RECEIPTS (ID_RECEIPT, ID_ITEM, NUM_ITEM, VALUE_ITEM) VALUES (1, 2, 4, 5.50); --4*5,50 = 22
COMMIT;

SELECT * FROM TEST.ZZ_RECEIPTS;
ID_RECEIPT    ID_ITEM   NUM_ITEM   VALUE_ITEM TOTAL_ITEM
---------- ---------- ---------- ------------ ----------
         1          1          3         4,50       13,5
         1          2          4         5,50         22

编辑：我想在这个字段上创建一个索引，类似于基于函数的索引。

谢谢！