为什么它返回不在范围之间的日期？答案

【问题标题】：Why it is returning the date which is not between the range?为什么它返回不在范围之间的日期？
【发布时间】：2019-06-25 02:26:42
【问题描述】：

我只想显示 2019 年 5 月 15 日至 23 日之间的数据。但为什么它还返回不在日期范围内的数据？

以下是我的查询

SELECT Appointment_ID, 
     WO_DespatchName, Despatch_Name AS WO_selectDespatchName,
     FORMAT(Appointment_DateTime, 'dd/MMM/yyyy hh:mm tt') AS Appointment_DateTime, 
     FORMAT(Appointment_ProposalSent, 'dd/MMM/yyyy') AS Appointment_ProposalSent,
     WO_MaidName, Maid_Name AS WO_selectMaidName,
     Appointment_Location, Appointment_FaceToFace, Appointment_Service, Appointment_Remarks, WO_Duration,
     Appointment_ContactID, Contact_Name AS Appointment_selectContactID
     FROM Appointments A
     LEFT JOIN Despatch ON Despatch_ID = WO_DespatchName 
     LEFT JOIN CustomerDetails ON Contact_ID = Appointment_ContactID 
     LEFT JOIN Maid ON Maid_ID = WO_MaidName 
     WHERE FORMAT(Appointment_DateTime, 'dd/MM/yyyy') BETWEEN '15/05/2019' AND '23/05/2019'
     AND (A.IsDelete = 0 OR A.IsDelete IS NULL)
     ORDER BY CONVERT(DateTime, Appointment_DateTime,101)  ASC

我得到的输出是https://drive.google.com/file/d/1VnrSET1V1eoFvEUUtRwXtQmKGWamURgV/view?usp=sharing

【问题讨论】：

那是因为您正在进行字符串比较，而不是日期比较。在比较日期之前不要格式化日期。
因为您将数据作为格式为dd/MM/yyyy 的字符串进行比较。将WHERE 子句更改为WHERE Appointment_DateTime >= '20190515' AND Appointment_DateTime < '20190524'

标签： sql-server

【解决方案1】：

您是在比较文本，而不是日期。因此，它将返回转换为字符串的日期从 15 到 23 之间的任何行。您需要在比较中使用日期数据类型：

 WHERE Appointment_DateTime >= CAST('20190515' AS date) AND Appointment_DateTime < CAST('20190524' AS date)

请注意，我在结束范围中添加了一天，因此 05/23/2019 11:59:59.9... PM 仍将被接受。 CAST 作为日期不是必需的，但可以提高可读性。

【讨论】：

最好使用date format that does not rely on language settings，即20190515。如果您确实想使用本地格式，请使用 CONVERT 和第三个参数的值。
真的，我会解决的。

【解决方案2】：

问题出在您的where 子句中。由于您的 Appointment_DateTime 是 datetime 格式。我期望该列的值类型为datetime。现在来查询，'23/05/2019' 是简单的字符串，因此无法将其与日期时间进行比较。首先，您需要将您的 from 和 to date 转换为 datetime 格式。

请试试这个（如果您只关心日期匹配）：

    SELECT Appointment_ID, 
         WO_DespatchName, Despatch_Name AS WO_selectDespatchName,
         FORMAT(Appointment_DateTime, 'dd/MMM/yyyy hh:mm tt') AS Appointment_DateTime, 
         FORMAT(Appointment_ProposalSent, 'dd/MMM/yyyy') AS Appointment_ProposalSent,
         WO_MaidName, Maid_Name AS WO_selectMaidName,
         Appointment_Location, Appointment_FaceToFace, Appointment_Service, Appointment_Remarks, WO_Duration,
         Appointment_ContactID, Contact_Name AS Appointment_selectContactID
         FROM Appointments A
         LEFT JOIN Despatch ON Despatch_ID = WO_DespatchName 
         LEFT JOIN CustomerDetails ON Contact_ID = Appointment_ContactID 
         LEFT JOIN Maid ON Maid_ID = WO_MaidName 
         WHERE FORMAT(Appointment_DateTime, 'dd/MM/yyyy') BETWEEN FORMAT('15/05/2019', 'dd/MM/yyyy') AND FORMAT('23/05/2019', 'dd/MM/yyyy') 
         AND (A.IsDelete = 0 OR A.IsDelete IS NULL)
         ORDER BY CONVERT(DateTime, Appointment_DateTime,101)  ASC

或者您可以尝试convert 将您的字符串转换为datetime 格式。

如有任何进一步的困惑，请随时询问。

【讨论】：