Question

我正在尝试创建一个查询，该查询根据用户输入的from和to日期从我的数据库返回可用的车辆。

这是我预订表中的日期。

Booking Table
booking_id     customer_id    reg_number    date_from    date_to    status
1              2              RH34 TJT      23-JAN-13    24-JAN-13  1
2              3              RJ54 FKF      26-JAN-13    26-JAN-13  1

以下是我的查询，如果我的日期不等于预订表中已有的日期，则可以使用。例如，如果我将22-JAN-13放到27-JAN-13，上表中的这两辆车将从结果中省略，因为它们已被预订。但是，如果我将23-JAN-13放入24-JAN-13，那么当天预订的汽车也不会因为预订而退回。

SELECT   *
FROM vehicles
INNER JOIN car_model ON vehicles.model_code = car_model.model_code
INNER JOIN manufacture ON car_model.manufacture_code = manufacture.manufacture_code
LEFT OUTER JOIN booking ON vehicles.reg_number = booking.reg_number
WHERE ((booking.date_from <= '23-JAN-13' OR booking.date_from >= '24-JAN-13')
        AND (booking.date_to <= '23-JAN-13' OR booking.date_to >= '24-JAN-13')
        AND booking.booking_status = 1);

因为我正在使用＆lt; =和＆gt; = equals部分将导致它省略它们，因为它们是相同的，或者我错了？

Answer 1

试试这个

SELECT   *
FROM vehicles
INNER JOIN car_model ON vehicles.model_code = car_model.model_code
INNER JOIN manufacture ON car_model.manufacture_code = manufacture.manufacture_code
LEFT OUTER JOIN booking ON vehicles.reg_number = booking.reg_number
WHERE ((booking.date_from < '23-JAN-13' OR booking.date_from > '24-JAN-13')
        AND (booking.date_to < '23-JAN-13' OR booking.date_to > '24-JAN-13')
        AND booking.booking_status = 1);

Answer 2

如果您正在寻找未在指定日期预订的车辆，您应该使用NOT EXISTS而不是加入VEHICLES表：

SELECT *
FROM   vehicles v
WHERE  NOT EXISTS (SELECT NULL
                   FROM   booking b
                   WHERE  b.reg_number = v.reg_number
                   AND    b.booking_status = 1
                   AND    ((b.date_to > to_date(:start_date,  'DD/MM/YYYY') AND b.date_from <= to_date(:start_date, 'DD/MM/YYYY')) OR 
                           (b.date_from <= to_date(:end_date, 'DD/MM/YYYY') AND b.date_to > to_date(:end_date, 'DD/MM/YYYY')) OR
                           (b.date_from <= to_date(:start_date, 'DD/MM/YYYY') AND b.date_to >= to_date(:end_date, 'DD/MM/YYYY')) OR
                           (b.date_from >= to_date(:start_date, 'DD/MM/YYYY') AND b.date_to <= to_date(:end_date, 'DD/MM/YYYY')))

用于预留的SQL select语句不起作用

2 个答案: