执行存储过程后在SQL Server中返回空表

Question

I have a problem with my stored procedure. I'm a bit confused about that because the stored procedure how I defined before it was working fine, but now it doesn't work.

Here the T-SQL code:

CREATE PROCEDURE [dbo].[getMonthMaxVal] 
    @from datetime,
    @to datetime
AS
BEGIN
    SET NOCOUNT ON;

    SELECT ds22.*
    FROM (SELECT 
                MAX(DAY(ds.datum)) AS TagMax,
                MONTH(ds.datum) AS MonatMax,
                YEAR(ds.datum) AS JahrMax,
                CONVERT(VARCHAR(10), MAX(ds.datum), 120) AS DatumMax
          FROM QR_DS022s ds
          WHERE ds.datum >= @from AND ds.datum <= @to
          GROUP BY MONTH(ds.datum), YEAR(ds.datum)) maxDate INNER JOIN QR_DS022s ds22 ON maxDate.DatumMax = ds22.datum
    ORDER BY ds22.datum
END

In the SQL Server 2008 R2 this stored procedure was working fine. In SQL Server 2014 it doesn't work. What's wrong?

EDIT:

When I'm executing the SP with the code:

EXECUTE ETF_DB.dbo.getMonthMaxVal @from='2014-01-01', @to='2014-04-01'

I'm getting an empty table with empty columns.

When I'm doing this:

EXECUTE ETF_DB.dbo.getMonthMaxVal @from='2014-01-01', @to='2014-04-02'

I'm getting an error message:

When converting a varchar data type to a datetime data type, the value is out of range.

Answer 1

While I can't see any data, and table structure, i'd remove the VARCHAR reference and use DATE across the board:

CREATE PROCEDURE [dbo].[getMonthMaxVal] 
    @from   DATE,
    @to     DATE
AS
BEGIN
    SET NOCOUNT ON;

    SELECT ds22.*
    FROM (  SELECT 
                    MAX(DAY(ds.datum)) AS TagMax,
                    MONTH(ds.datum) AS MonatMax,
                    YEAR(ds.datum) AS JahrMax,
                    CONVERT(DATE, MAX(ds.datum)) AS DatumMax
              FROM QR_DS022s ds
              WHERE ds.datum >= @from AND ds.datum <= @to
              GROUP BY MONTH(ds.datum), YEAR(ds.datum)) maxDate 
          INNER JOIN QR_DS022s ds22 
            ON maxDate.DatumMax = CONVERT(DATE, ds22.datum)
    ORDER BY ds22.datum
END

Let me know if that fixes your problem.