mysql - 比较 mySQL 中的多个日期

Question

我们正在开发一个需要支持拆分预约的预约系统。这些约会有前半部分，休息期间可以预订其他东西，然后是下半部分。

系统还支持具有标准开始和结束的正常预订。

我们需要检查数据库，看看是否有任何现有预订与我们希望进行的预订重叠。

我们以前在 PHP 中完成过此操作，但在这种情况下需要仅在 mysql 中完成。

预订表有:

开始日期(总是)splitStartDate(有时)splitEndDate(有时)结束日期(总是)

当 splitStartDate 和 splitEndDate 未用于预订时，它们的值为 0000-00-00 00:00:00

我们开始尝试用 ifs 构建 mysql 语句，但它看起来长得离谱。

    "SELECT *
     FROM bookings WHERE
    (
        (
            IF(
                splitStartDate != "0000 00:00:00",
                IF(
                    ((CONVERT_TZ('" . $requested_start_time->format("Y-m-d G:i:s") . "', \"$tzone\", \"UTC\") >= startDate) AND (CONVERT_TZ('" . $requested_start_time->format("Y-m-d G:i:s") . "', \"$tzone\", \"UTC\") < splitStartDate))
                    OR
                    ((CONVERT_TZ('" . $requested_start_time->format("Y-m-d G:i:s") . "', \"$tzone\", \"UTC\") >= splitEndDate) AND (CONVERT_TZ('" . $requested_start_time->format("Y-m-d G:i:s") . "', \"$tzone\", \"UTC\") < endDate))
                    , 1, 0
                ),
                IF(
                    (CONVERT_TZ('" . $requested_start_time->format("Y-m-d G:i:s") . "', \"$tzone\", \"UTC\") < endDate) AND (CONVERT_TZ('" . $requested_start_time->format("Y-m-d G:i:s") . "', \"$tzone\", \"UTC\") >= startDate), 1, 0        
                )
            ) = 1
        )
        OR
        (
            IF(
                splitStartDate != "0000-00-00 00:00:00",
                IF(
                    ((CONVERT_TZ('" . $requested_end_time->format("Y-m-d G:i:s") . "', \"$tzone\", \"UTC\") > startDate) AND (CONVERT_TZ('" . $requested_end_time->format("Y-m-d G:i:s") . "', \"$tzone\", \"UTC\") <= splitStartDate))
                    OR
                    ((CONVERT_TZ('" . $requested_end_time->format("Y-m-d G:i:s") . "', \"$tzone\", \"UTC\") > splitEndDate) AND (CONVERT_TZ('" . $requested_end_time->format("Y-m-d G:i:s") . "', \"$tzone\", \"UTC\") <= endDate))
                    , 1, 0
                ),
                IF(
                    (CONVERT_TZ('" . $requested_end_time->format("Y-m-d G:i:s") . "', \"$tzone\", \"UTC\") > startDate) AND (CONVERT_TZ('" . $requested_end_time->format("Y-m-d G:i:s") . "', \"$tzone\", \"UTC\") <= endDate), 1, 0        
                )
            ) = 1           
        )
        OR 
        (

我们知道必须有一种更简单的方法来做到这一点，但一直对它是什么感到困惑。我们很乐意就如何为此构建 mysql 查询提出任何建议。

在检查可用性时，我们一直在运行以下检查(很抱歉这花了多长时间，但这就是问题所在):

------------
all simple

requested startDate is in-between existing startDate and existing endDate
requested endDate is in-between existing startDate and existing endDate
existing startDate is in-between requested startDate and requested endDate
existing endDate is in-between requested startDate and requested endDate



-------------
advanced desired / simple existing

requested startDate is in-between existing startDate and existing endDate
requested splitStartDate is in-between existing startDate and existing endDate
existing startDate is in-between requested startDate and requested splitStartDate
existing endDate is in-between requested startDate and requested splitStartDate

requested splitEndDate is in-between existing startDate and existing endDate
requested endDate is in-between existing startDate and existing endDate
existing startDate is in-between requested splitEndDate and requested endDate
existing endDate is in-between requested splitEndDate and requested endDate


------
simple desired / advanced existing

requested startDate is in-between existing startDate and existing splitstartDate
requested endDate is in-between existing startDate and existing splitstartDate
existing startDate is in-between requested startDate and requested endDate
existing splitstartDate is in-between requested startDate and requested endDate

requested startDate is in-between existing splitEndDate and existing endDate
requested endDate is in-between existing splitEndDate and existing endDate
existing splitEndDate is in-between requested startDate and requested endDate
existing endDate is in-between requested startDate and requested endDate

-----
advanced both

1st 1/2 both
requested startDate is in-between existing startDate and existing splitstartDate
requested splitStartDate  is in-between existing startDate and existing splitstartDate
existing startDate is in-between requested startDate and requested splitStartDate
existing splitstartDate  is in-between requested startDate and requested splitStartDate

2/2 desired  1/2 existing
requested splitEndDate  is in-between existing startDate and existing splitstartDate
requested endDate is in-between existing startDate and existing splitstartDate
existing startDate is in-between requested splitEndDate and requested endDate
existing splitstartDate is in-between requested splitEndDate and requested endDate

1/2 desired 2/2 existing
requested startDate is in-between existing splitEndDate and existing endDate
requested splitStartDate  is in-between existing splitEndDate and existing endDate
existing splitEndDate  is in-between requested startDate and requested splitStartDate
existing endDate is in-between requested startDate and requested splitStartDate

2nd 1/2 all
requested splitEndDate is in-between existing splitEndDate and existing endDate
requested endDate is in-between existing splitEndDate and existing endDate
existing splitEndDate is in-between requested splitEndDate and requested endDate
existing endDate is in-between requested splitEndDate and requested endDate

非常感谢

Answer 1

我的猜测是，如果您清理正在执行的日期操作，您会喜欢您的查询。

将其移至 mysql 变量:

SET @REQUEST = (CONVERT_TZ('" . $requested_start_time->format("Y-m-d G:i:s") . "', \"$tzone\", \"UTC\");

然后您的代码如下所示:

        IF(
            splitStartDate != "0000 00:00:00",
            IF(
                (@REQUEST >= startDate AND @REQUEST < splitStartDate)
                OR
                (@REQUEST >= splitEndDate) AND @REQUEST < endDate))
                , 1, 0
            ),
            IF(
                (@REQUEST < endDate AND @REQUEST >= startDate), 1, 0        
            )
        ) = 1

这不无道理。使用“X = 1”对我来说就像一个 where 子句，所以我更愿意看到

select count(*)
from bookings
where
(
    splitStartDate is not null
        and (
             (@REQUEST >= startDate AND @REQUEST < splitStartDate)
             OR
             (@REQUEST >= splitEndDate) AND @REQUEST < endDate))
        )
)
OR
(
    splitStartDate is null
        and (
            @REQUEST < endDate AND @REQUEST >= startDate
        )
)

祝你好运!