如果选择的日期等于或大于数据中的日期，则日期之间的查询仅返回结果

Question

I have two queries that are using a between clause to produce a date range, where the date is passed in through a VB.net program:

select
 w.plate,
 Description,
 Date_in,
 time_in,
 Date_out,
 Time_out,
 Date_out-Date_in as "Days on Site",
 Time_out-Time_in as "Duration on Site (Hrs)"
from tbl_stay S
inner join tblwhitelist W
on S.plate=W.plate
where Date_in between "1/06/2013" and "25/09/2013"

and

select
Plate,
Date_in,
Time_in,
Date_out,
Time_out,
Date_out-Date_in as "Days on site",
Time_out-Time_in as "Duration on site (Hrs)"
from tbl_stay
where plate not in (Select plate from tblwhitelist)
and date_in between "1/07/2013" and "1/08/2013"

For testing, i have a block of data that has the date "25/07/2013" for both in and out. These queries only seem to produce results if the day of the month is greater than the day mentioned in the data (25)

for example: the dates mentioned in the queries above:

Date_in between "1/06/2013" and "25/09/2013"

will yield a result, however

date_in between "1/07/2013" and "1/08/2013"

will not. even though the date included in the test data (25/07/2013) is within both of these ranges.

I am completely stumped. What could possibly be going on here? any assistance would be appreciated

Answer 1

When you use double quotes you are comparing text-strings , not dates . Literal meaning of 01/07/2013 is less than 25/01/2013 , basically these strings are compared character by character. If you look at the first character in both strings, then 0 is less than 2 .

Answer 2

The answer is not to use Between.

Separate that line in the WHERE clause into two and explicitly specify whether or not to include that date by using a >= or just a > .

AND date_in > "1/07/2013" or date_in >= "1/07/2013"

AND date_in < "1/08/2013" or date_in <= "1/08/2013"