比较mySQL中的多个日期

时间：2011-04-19 23:54:17

标签： mysql date datetime calendar convert-tz

我们正在开发一个需要支持拆分约会的预订系统。这些约会有上半场，休息期间可以预订其他东西，然后是下半场。

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，看看是否有任何预订与我们希望的预订重叠。

我们之前已经在PHP中完成了这项工作，但在这种情况下只需要在mysql中完成。

预订表有：

startDate（总是） splitStartDate（有时） splitEndDate（有时） endDate（总是）

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

我们开始尝试用ifs构建mysql语句，但看起来非常漫长。

    "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为简单的方法来做到这一点，但却对它是什么感到难过。我们喜欢有关如何为此构建mysql查询的任何建议。

在检查可用性时，我们一直在运行以下检查（对不起，这是多长时间，但这就是问题）：

------------
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

1 个答案:

答案 0 :(得分：2)

我的猜测是，如果你清理你正在做的日期操作，你会喜欢你的查询。

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

这不是不合理的。使用“X = 1”对我来说就像where子句，所以我更愿意看

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！

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