Add days to pieced together date - sql

Question

I have a database where, for some reason, the dates are put in like 1yymmdd. I have been asked to create a field in a query that adds 30 days to this date. I have transformed the date into a readable format by the following:
SUBSTRING(Datefield, 4, 2) + '/' + SUBSTRING(Datefield, 6, 2)
+ '/' + SUBSTRING(Datefield, 2, 2) AS LookLikeDate
I placed this in a view, and attempted to then:
DATEADD(dd,30, CONVERT(datetime, v.[LookLikeDate], 103)
I keep getting an error that says
The conversion of a varchar data type to a datetime data type resulted in an out-of-range value.
I then attempted to define in my View statement so that this field would be datetime from the start:
CONVERT(datetime, SUBSTRING(Datefield, 4, 2) + '/'
+ SUBSTRING(Datefield, 6, 2) + '/'
+ SUBSTRING(Datefield, 2, 2), 103) AS LookLikeDate
When I got an error in that definition, to where I couldn't use the view at all, I changed the datetime to Char(8), which gave me the same varchar error I got previously.
Am I going about this wrong, and is there a way to add these days to this rediculous date format?

Answer 1

Just to add 30 days you can do
SELECT DATEADD(dd, 30, RIGHT(datefield, 6)) NewDate
FROM table1
To add 30 days and convert back to that format use
SELECT '1'+ CONVERT(VARCHAR(6), DATEADD(dd, 30, RIGHT(datefield, 6)), 12) NewDate
FROM table1
If you were to have following sample data
| DATEFIELD |
|-----------|
| 1130801 |
| 1130812 |
| 1120827 |
Then the output of two above mentioned queries would be
| NEWDATE |
|----------------------------------|
| August, 31 2013 00:00:00+0000 |
| September, 11 2013 00:00:00+0000 |
| September, 26 2012 00:00:00+0000 |
and
| NEWDATE |
|---------|
| 1130831 |
| 1130911 |
| 1120926 |
respectively.
Here is SQLFiddle demo