sql-server - SQL Server 2008 R2 bug 还是什么？

Question

我观察到一种奇怪的行为。以下与将 nvarchar 子字符串转换为 tinyint 相关的代码工作正常:

DECLARE @s nvarchar(50) = N'Line 1'
DECLARE @n tinyint = SUBSTRING(@s, 6, 10)

SELECT
        N'Line 1' AS explicit_nvarchar,
        @s AS nvarchar_variable,
        SUBSTRING(@s, 6, 10) AS nvarchar_substring
        , @n AS tinyint_var_converted_earlier
        , CAST(SUBSTRING(@s, 6, 10) AS tinyint) AS cast_sub_var
        , CAST(SUBSTRING(N'Line 1', 6, 10) AS tinyint) AS cast_nvarchar_substr

我可以在 Microsoft SQL Server Management Studio 中观察到以下输出:

。

但是，如果注释行未注释，则尝试处理表中的 SELECT 的代码将失败:

Select 
    [order].[identifier] As [order_identifier],
    [plan_data].[starts_on] As [from],
    [plan_data].[ends_on] As [to],
    [workplace].[identifier] AS line_identifier,
    SUBSTRING([workplace].[identifier], 6, 10) AS line_no_str
    --, CAST(SUBSTRING([workplace].[identifier], 6, 10) AS int) AS line_no
From 
    ...

带有注释行...

但未注释行(均用于转换为 tinyint 或 int)...

更新:奇怪。我已将最后一行添加到 WHERE 以检查所有行是否包含'Line...

Where
    [plan].[identifier] = @lPlanIdentifier And
    (
        [plan_data].[starts_on] Between @fromUTC And @toUTC Or
        [plan_data].[ends_on] Between @fromUTC And @toUTC)
    AND LEFT([workplace].[identifier], 4) = N'Line'

...突然间它也适用于未注释的行。我怎样才能找出导致问题的原因？

更新2:我应该遵循Hamlet Hakobyan's answer与发布时完全相同。当查看表格内部时，我可以看到:

Answer 1

identifier 列中有值，SUBSTRING([workplace].[identifier], 6, 10) 返回 ined。

尝试这个查询:

SELECT * FROM [workplace]
WHERE SUBSTRING([identifier], 6, 10) = N'ined'