如何在2字符串日期之间使用命令

Question

我正在使用以下选择查询，但问题是IssueDate列位于varchar且未提供正确的结果。在SQL中命令字符串日期之间是否有任何使用方法：

SELECT Pkid AS [Bill Id],
       InvoiceNumber,
       InvoiceType,
       IssueDate,
       FinalTotal
FROM tblInvoiceMain
WHERE IssueDate BETWEEN '01 June 2016' AND '06 June 2016'
ORDER BY Pkid DESC

输出：

Answer 1

使用CONVERT将IssueDate投射到DATE类型。此外，使用日期常量时，请使用YYYYMMDD格式。

SELECT 
    Pkid AS [Bill Id], InvoiceNumber, InvoiceType, IssueDate, FinalTotal 
FROM tblInvoiceMain 
WHERE
    CONVERT(DATE, IssueDate, 106) BETWEEN CAST('20160601' AS DATE) AND CAST('20160606' AS DATE)
ORDER BY Pkid DESC

但是，如果您在IssueDate上有索引，则会阻止使用它。我的建议是修复您的架构并使用正确的数据类型来存储您的值。

Answer 2

SELECT Pkid AS [Bill Id],
       InvoiceNumber,
       InvoiceType,
       IssueDate,
       FinalTotal
FROM tblInvoiceMain
WHERE CAST(IssueDate AS DATE) BETWEEN '20160601' AND '20160606'
ORDER BY Pkid DESC

如果执行时间非常长：

ALTER TABLE dbo.tblInvoiceMain
    ADD IssueDate2 AS CAST(IssueDate AS DATE)
GO
CREATE NONCLUSTERED INDEX ix
    ON dbo.tblInvoiceMain (IssueDate2)
    INCLUDE (Pkid, InvoiceNumber, InvoiceType, IssueDate, FinalTotal)
GO

SELECT Pkid AS [Bill Id],
       InvoiceNumber,
       InvoiceType,
       IssueDate,
       FinalTotal
FROM tblInvoiceMain
WHERE IssueDate2 BETWEEN '20160601' AND '20160606'
ORDER BY Pkid DESC