oracle中创建视图，如果一个（order_no）字段为null时，显示为(group_no)另一个字段的值?

Question

如题所述

Answer 1

CREATE OR REPLACE VIEW 视图名称 AS
SELECT
其他字段,
nvl(order_no, group_no)
FROM
表名
WHERE 条件';

Answer 2

select case when order_no is null then group_no else order_no end from table