Tsql T-SQL:从字符串转换日期和/或时间时，转换失败

下面是用于捕获SQL表上的更新/插入的触发器。我不知道为什么，但每当更新完成时，我都会收到错误消息转换失败，从字符串转换日期和/或时间。以下是事务日志表的结构：

CREATE TABLE [dbo].[TransactionLog](
    [Id] [int] IDENTITY(1,1) NOT NULL,
    [TransactionDate] [datetime] NOT NULL,
    [Operator] [varchar](35) NOT NULL,
    [TableName] [varchar](50) NOT NULL,
    [Action] [char](1) NOT NULL,
    [TableString] [nvarchar](255) NOT NULL,
    [UserId] [char](6) NULL,
 CONSTRAINT [PK_TransactionLog] PRIMARY KEY CLUSTERED 
(
    [Id] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON, FILLFACTOR = 90) ON [PRIMARY]
) ON [PRIMARY]

以下是正在更新的表：

CREATE TABLE [dbo].[AgentContEd](
    [Id] [int] IDENTITY(1,1) NOT NULL,
    [sNumber] [int] NOT NULL,
    [StateCode] [char](3) NOT NULL,
    [CourseCode] [char](6) NOT NULL,
    [DateTaken] [date] NOT NULL,
    [ExpirationDate] [date] NULL,
    [CourseHours] [smallint] NOT NULL,
    [Method] [varchar](15) NULL,
    [LastChangeOperator] [char](8) NOT NULL,
    [LastChangeDate] [datetime] NOT NULL,
    [ControlId] [int] NULL,
 CONSTRAINT [PK_AgentContEd] PRIMARY KEY CLUSTERED 
(
    [Id] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON, FILLFACTOR = 90) ON [PRIMARY]
) ON [PRIMARY]

这是引起头痛的导火索

BEGIN
    INSERT INTO dbo.TransactionLog 
    (
        TransactionDate, 
        Operator, 
        TableName, 
        Action, 
        TableString, 
        UserId
    )
    SELECT 
        LastChangeDate,
        'Op',
        @tableName,
        @action,
        CAST(
          'ID:'             + CAST(ISNULL(Id,             'NULL') as char(4))
        + ' SymNum:'        + CAST(ISNULL(sNumber,  'NULL') as char(10))
        + ' StateCode:'     + ISNULL(StateCode,           'NULL')
        + ' DateTaken:'     + CAST(ISNULL(DateTaken,      'NULL') as nvarchar(9))
        + ' ExpDate:'       + CAST(ISNULL(ExpirationDate, 'NULL') as nvarchar(9))
        + ' CourseCode:'    + ISNULL(CourseCode,          'NULL')
        + ' Hours:'         + CAST(ISNULL(CourseHours,    'NULL')  as char(3))
        + ' Mthd:'          + ISNULL(Method,              'NULL')
        As char(255)), 
        LastChangeOperator
    FROM inserted
END

试一试

我使用了

varchar

，因为如果要在末尾将字符串强制转换为

char

，那么使用

nvarchar

似乎毫无意义

此外，您可能需要将

CONVERT

与样式一起使用，而不是

CAST

来存储有用的内容<代码>选择CAST（getdate（）作为nvarchar（9））为我返回20年9月28日的

这是插入触发器之前还是之后？
    + ' DateTaken:'     + ISNULL(CAST(DateTaken as varchar(9)),      'NULL')
    + ' ExpDate:'       + ISNULL(CAST(ExpirationDate as varchar(9)), 'NULL')