Sql-server – SQL Server datetime column datatype stores offset

We solved this in Oracle using function based indexes. Although, it's not quite as flexible, you can accomplish similar in SQL Server using computed columns.

If all of the information you need is in the table, and you meet all of the ownership requirements (outlined in the second article) then I would recommend making the date/time field a computed column on the table, and then add an index to the computed column.

Computed Columns:

http://technet.microsoft.com/en-us/library/ms191250(v=sql.105).aspx

Indexing Computed Columns:

http://msdn.microsoft.com/en-us/library/ms189292

Well, first off, you should fix your table and store date/time data using the right kind of column, and not breaking it up for reasons unknown. Whose decision was it to store a time as a CHAR(6)? Can you think of a single good reason for that? Where do you store the date? Was that 1 PM today, last Tuesday, or October 2012 sometime? This really should be a single datetime column. Have the "designers" please read this and this.

But barring that (funny how every time you suggest a table change, they say they can't change the table):

DECLARE @x TABLE(y CHAR(6));

INSERT @x(y) VALUES('131329');

SELECT DATEADD(MINUTE,5,CONVERT(TIME(0),STUFF(STUFF(y,5,0,':'),3,0,':'))) 
  FROM @x;

Result:

13:18:29

If you find that query ugly and tedious, good! There's a good reason: You're storing your data wrong.

And this won't be the last problem you have with this design, either. What is stopping someone from inserting 967286 or foobar or <empty string> in your CHAR(6) column? If you need to work around that problem, you can use TRY_CONVERT() in 2012 and up (please always specify version with a version-specific tag), or a CASE expression in earlier versions.

DECLARE @x TABLE(y CHAR(6));

INSERT @x(y) VALUES('foobar');

-- 2012:
SELECT DATEADD(MINUTE,5,TRY_CONVERT(TIME(0), STUFF(STUFF(y,5,0,':'),3,0,':'))) 
  FROM @x;

-- older:
SELECT DATEADD(MINUTE,5,CONVERT(TIME(0),
CASE WHEN ISDATE(STUFF(STUFF(y,5,0,':'),3,0,':'))=1 THEN
    STUFF(STUFF(y,5,0,':'),3,0,':') END))
  FROM @x;