Implicit Conversion from data type sql_variant to datetime is not allowed.

Question

 Getting a odd error. This code was working perfectly before a SQLServer upgrade.
The linked database is working, I'm able to pull up data from it in separate queries just fine.
I'm getting the following error.
Implicit conversion from data type sql_variant to datetime is not allowed. Use the CONVERT function to run this query.
Invalid column name 'TotalDay'. (.Net SqlClient Data Provider)
can anyone spot the issue? I've tried sever variations of the same code, but still get the same thing.
If I put this section in a query by it self it works just fine.
( DATEDIFF(ss,
CONVERT(VARCHAR(10),( SELECT TOP ( 1 )
TimeDate
FROM [nav].AcsLog.dbo.EvnLog AS X3
WHERE UDF2 = E.No_
AND CONVERT(VARCHAR(10), X3.TimeDate, 101) = CONVERT(VARCHAR(10), @sdate, 101)
ORDER BY TimeDate ASC
),101),
CONVERT(VARCHAR(10),( SELECT TOP ( 1 )
TimeDate
FROM [nav].AcsLog.dbo.EvnLog AS X4
WHERE UDF2 = E.No_
AND CONVERT(VARCHAR(10), X4.TimeDate, 101) = CONVERT(VARCHAR(10), @sdate, 101)
ORDER BY TimeDate DESC
),101)) ) AS TotalDayBadge ,

Answer 1

>ANDCONVERT(VARCHAR(10),X3.TimeDate,101)=CONVERT(VARCHAR(10),@sdate,101)
It is not a good idea to use string dates for predicates in WHERE clauses.
Use DATETIME or DATE in predicates.
If you are not interested in the time part of DATETIME, use DATE datatype.
Example:
SELECT CONVERT(DATE, getdate());
-- 2014-08-25
Datetime conversions:
http://www.sqlusa.com/bestpractices/datetimeconversion/
Between dates:
http://www.sqlusa.com/bestpractices2008/between-dates/
Kalman Toth Database & OLAP Architect
SQL Server 2014 Design & Programming
New Book / Kindle: Exam 70-461 Bootcamp: Querying Microsoft SQL Server 2012