SQL Express does NOT have Agent service

Even there's an "SQL Server Agent (SQLEXPRESS)" service inside the "SQL Server Services" list of Sql Server Configuration Manager, you can never be started it! All EXPRESS editions do NOT have Agent service. Refers to the "Features Supported by the Editions of SQL Server 2012".
http://msdn.microsoft.com/en-us/library/cc645993.aspx#Mgmt_tools

SQL 2012 TRY_CONVERT

There're new built-in functions in SQL2012 which can be used to trying convert/cast/parse a value into specified type, and if the conversion can't be done, it won't raise any error but return a NULL value. I found it very handy for parsing XML into SQL data. The example below demonstrate how to use TRY_CONVERT.

SELECT TRY_CONVERT(date, dbo.ufnBlankToNull(T.c.value('./@tradedate', 'varchar(50)')), 120),
TRY_CONVERT(float, dbo.ufnBlankToNull(T.c.value('./@PX_OPEN', 'varchar(50)')))
FROM @x.nodes('/PriceHistory/instrument') AS I(c)
CROSS APPLY I.c.nodes('./trade') AS T(c)

As the TRY_CONVERT function will convert blank string to 0 for numeric type and '1900-01-01' for date type, which isn't what I want. So I create a custom scalar function as below to convert blank string to NULL before input the value into TRY_CONVERT.
CREATE FUNCTION ufnBlankToNull
(
    @s nvarchar(max)
)
RETURNS nvarchar(max)
AS
BEGIN
    RETURN LTRIM(RTRIM(NULLIF(@s, '')))
END