Question

我有以下SQL

SELECT CASE
        WHEN B.bookingId = P.bookingId
        THEN 1
        ELSE 0
        END AS PAID
        FROM Booking B
        LEFT OUTER JOIN Payment P ON P.bookingId = B.bookingId

输出3行; 1,1和0

我想扩展此查询以输出0值的预订详情。

我该怎么做？

由于

Answer 1

select * from booking
where booking_id not in ( select bookingid from payment )

Answer 2

如果您需要在付款时有一个列== 0，那么您还可以在付款时获得该列== 1.

试试这个：

select
  case
    when booking.bookingId = payment.bookingId then
      1
    else
      0
  end as paid,
  column_detail1,
  column_detail2
from
  booking
  left outter join payment on payment.bookingId = booking.bookingId

如果您只想在付费时选择信息为0，则可以尝试：

select
  paid_flag.paid,
  booking.detail1,
  booking.detail2
from
  (
    select
      case
        when booking.bookingId = payment.bookingId then
          1
        else
          0
      end as paid,
      booking.bookingId
    from
      booking
        left outter join payment on payment.bookingId = booking.bookingId
  ) paid_flag
  join booking on paid_flag.bookingId = booking.bookingId
where
  paid_flag.paid == 0

上述查询似乎可以进行优化。

Answer 3

如果我理解你的问题，这将提供两者的详细信息。然后你可以忽略1个细节。

  SELECT CASE
            WHEN B.bookingId = P.bookingId
            THEN 1
            ELSE 0
            END AS PAID,
            B.details
            FROM Booking B
            LEFT OUTER JOIN Payment P ON P.bookingId = B.bookingId

其他明智的可能

SELECT CASE
            WHEN B.bookingId = P.bookingId
            THEN 1
            ELSE 0
            END AS PAID,
            WHEN B.bookingId = P.bookingId
            THEN ''
            ELSE B.details
            END AS UNPAIDDETAILS,
            FROM Booking B
            LEFT OUTER JOIN Payment P ON P.bookingId = B.bookingId

Answer 4

如果您使用的是SQL 2005 +

;with cte as (
SELECT B.BookingId, 
        CASE
        WHEN B.bookingId = P.bookingId
        THEN 1
        ELSE 0
        END AS PAID
        FROM Booking B
        LEFT OUTER JOIN Payment P ON P.bookingId = B.bookingId
)
select B.*
from Booking B
inner join cte
   on B.BookingId = cte.BookingId
where cte.PAID = 0

Answer 5

因为Booking中的行将始终存在于结果集中（因为它是JOIN中的左侧表），您只需要包含要返回列列表的列：

 SELECT CASE
    B.Column1Name,
    B.Column2Name,
    WHEN B.bookingId = P.bookingId
    THEN 1
    ELSE 0
    END AS PAID
    FROM Booking B
    LEFT OUTER JOIN Payment P ON P.bookingId = B.bookingId

这将显示所有记录的预订详细信息。

如果您只对未付费记录感兴趣，请在WHERE子句中添加一些内容，将输出限制为仅限这些记录：

 SELECT CASE
    B.Column1Name,
    B.Column2Name,
    WHEN B.bookingId = P.bookingId
    THEN 1
    ELSE 0
    END AS PAID
    FROM Booking B
    LEFT OUTER JOIN Payment P ON P.bookingId = B.bookingId
    WHERE P.bookingID IS NOT NULL

Answer 6

SELECT B.BOOKINGID AS ID, 'PAID' AS PAYMENT_STATUS
FROM BOOKING B
WHERE B.BOOKINGID IN (SELECT PAYMENT.BOOKINGID FROM PAYMENT)

UNION ALL

SELECT B.BOOKINGID, 'UNPAID'
FROM BOOKING B
WHERE B.BOOKINGID NOT IN (SELECT PAYMENT.BOOKINGID FROM PAYMENT)

查询找不到付费的用户？

6 个答案: