SELECT Between dates almost working - sql-server-2008

Question

My problem is likely all about date formatting in a SELECT.
In an asp file I open an ADO Recordset wanting to retrieve rows of a MS SQL table that fall between date1 (08/15/2013) and date2 (08/22/2013) (i.e., the previous 7 days from today's date.)
The SELECT does retrieve the appropriate 2013 rows but also retrieves rows going back to 08/15/2012.
Here is the SELECT:
oRS.Source = "SELECT * FROM aTable WHERE entry_Date BETWEEN '" & resultLowerDate & "' AND '" & resultCurrentDate & "' AND entry_Status <> 'INACTIVE'"
resultLowerDate = 08/15/2013 and resultCurrentDate = 08/22/2013.
The table is set up as follows with resultCurrentDate = "08/22/2013":
entry_Status entry_Date (varchar) LastName FirstName SELECT Result
INITIAL 08/15/2012 Smith Jim YES
INACTIVE 08/21/2012 Green Tom no
INITIAL 08/22/2013 Jones Mary yes
FOLLOWUP 08/22/2013 Jones Mary yes
FOLLOWUP 08/22/2013 Brown Sally yes
FOLLOWUP 08/22/2013 Smith Jim yes
Any thoughts as to why the INITIAL 08/15/2012 row gets selected along with the other rows that meet the SELECT query?

Answer 1

STOP STORING DATES IN VARCHAR COLUMNS! And STOP CONCATENATING STRINGS, USE PROPER PARAMETERS.
Sorry to yell, but we are getting multiple questions a day where people use the wrong data type for some unknown and probably silly reason, and these are the problems it leads to.
The problem here is that you are comparing strings. Try:
"... WHERE CONVERT(DATETIME, entry_date, 101)" & _
" >= CONVERT(DATETIME, '" & resultLowerDate & "', 101)" & _
" AND CONVERT(DATETIME, entry_date, 101)" & _
" < DATEADD(DAY, 1, CONVERT(DATETIME, '" & resultCurrentDate & "', 101))"
Or better yet, set resultLowerDate and resultUpperDate to YYYYMMDD format, then you can say:
"... WHERE CONVERT(DATETIME, entry_date, 101) >= '" & resultLowerDate & "'" & _
" AND CONVERT(DATETIME, entry_date, 101) < DATEADD(DAY, 1, '" & resultCurrentDate & "'"
Note that I use an open-ended range (>= and <) instead of BETWEEN, just in case some time slips into your VARCHAR column.
Also note that this query could fail because garbage got into your column. Which it can, because you chose the wrong data type. My real suggestion is to fix the table and use a DATE or DATETIME column.

Answer 2

The fact that your entry_Date column is a varchar field and not an actual date is the problem. If you cast it to a datetime during the select, you'll get the results you expect.
select *
from aTable
where cast(entry_Date as datetime) between '08/15/2013' and '08/22/2013'
Sql Fiddle link