如果沒有別的幫助,你可以還提供一個空表:
CREATE VIEW bla AS
SELECT blabla
WHERE HOUR(NOW()) BETWEEN 9 AND 18
也許你可以添加一個UNION
:
UNION
SELECT 'You','should','be','at','home','now!'
WHERE HOUR(NOW()) NOT BETWEEN 9 AND 18
細化的第一個想法的:你可以爲連接(如果甲骨文發生創建一個0或1的行視圖計算與每行SYSDATE表達,這可能是比較慢):
CREATE VIEW STAFF_ORDERVIEW_ALLOWED(current_sys_date) AS
SELECT sysdate
WHERE SYSDATE BETWEEN trunc(sysdate) + 9/24 AND trunc(sysdate) + 18/24;
然後你只需加入
CREATE VIEW STAFF_ORDERVIEW_ATHOURS(current_sys_date, ordernumber, customernumber,
dateorderplaced, deliveryinstruction, scheduleid) AS
SELECT sysdate, ORDERNUMBER, CUSTOMERNUMBER,
DATEORDERPLACED, DELIVERYINSTRUCTION, SCHEDULEID
FROM STAFF_ORDERVIEW_ALLOWED
INNER JOIN ORDERS;
您正在使用哪些DBMS? (PostgreSQL,Oracle,DB2,...) – 2012-03-11 23:16:26