Question

我正在努力解决这个错误：从字符串转换日期和/或时间时转换失败。

从我的谷歌搜索来看，这是一个常见的错误，但到目前为止我没有尝试过任何工作。我已经尝试将@startdate转换为datetime和varchar而不管它，如下例所示。

我也尝试过对字段名称和参数名称使用convert，虽然不可否认，我可能只是错误地使用了语法。

ALTER PROCEDURE [dbo].[customFormReport]
(
    @formid int,
    @startdate DATETIME
)
AS
BEGIN
SET NOCOUNT ON

DECLARE @cols AS NVARCHAR(MAX),
    @query  AS NVARCHAR(MAX)

select @cols = STUFF((SELECT distinct ',' + QUOTENAME(fieldname) from FormResponse WHERE FormID = @formid AND value IS NOT NULL FOR XML PATH(''), TYPE).value('.', 'NVARCHAR(MAX)') 
        ,1,1,'')

set @query = 'SELECT FormID, FormSubmissionID,' + @cols + ' from 
             (
                SELECT FormID, FormSubmissionID, fieldname, value
                FROM FormResponse WHERE FormID = ' + CAST(@formid AS VARCHAR(25)) + ' AND createDate > ' + @startdate + '
             ) x
            pivot 
            (
                max(value)
                for fieldname in (' + @cols + ')
            ) p '

execute(@query)

编辑：查询有效，除非我添加导致错误的位：

' AND createDate > ' + @startdate + '

Answer 1

问题是您正在尝试将datetime连接到varchar sql字符串。你需要转换它：

convert(varchar(10), @startdate, 120)

所以完整的代码将是：

ALTER PROCEDURE [dbo].[customFormReport]
(
    @formid int,
    @startdate DATETIME
)
AS
BEGIN
SET NOCOUNT ON

DECLARE @cols AS NVARCHAR(MAX),
    @query  AS NVARCHAR(MAX)

select @cols = STUFF((SELECT distinct ',' + QUOTENAME(fieldname) from FormResponse WHERE FormID = @formid AND value IS NOT NULL FOR XML PATH(''), TYPE).value('.', 'NVARCHAR(MAX)') 
        ,1,1,'')

set @query = 'SELECT FormID, FormSubmissionID,' + @cols + ' from 
             (
                SELECT FormID, FormSubmissionID, fieldname, value
                FROM FormResponse 
                WHERE FormID = ' + CAST(@formid AS VARCHAR(25)) + ' 
                  AND createDate > ''' + convert(varchar(10), @startdate, 120) + '''
             ) x
            pivot 
            (
                max(value)
                for fieldname in (' + @cols + ')
            ) p '

execute(@query)

Answer 2

当您动态构建SQL语句时，日期值需要用单引号括起来。每当构建动态语句时，请执行SELECT @query并确保结果看起来正确。

对于您的示例，您需要'WHERE createdate > ''' + covert(varchar(10), @startdate, 111) + '''

那将输出：WHERE createdate > '2013/05/29'

如果没有单引号，您将拥有：WHERE createdate > 2013/05/29

从字符串转换日期和/或时间时转换失败

2 个答案: