php mysql getting count WHERE BETWEEN AND - php

Question

Hey i have a little problem when i'm trying to get count of rows from table, where date is BETWEEN 2012-09-01 AND 2012-09-32...
Could you please tell me where's the problem?
$month = date(m);
$year = date(Y);
$day_start = '01';
$day_end = '32';
$from = $year.'-'.$month.'-'.$day_start;
$till = $year.'-'.$month.'-'.$day_end;
$result1 = $mysqli->query("SELECT COUNT(id) FROM `dreams` WHERE dream_state='dream' AND date BETWEEN $from AND $till");
$row1 = $result1->fetch_row();
$this_dream = $row1[0];
i've tryed to convert the string to time and from time to date like this:
$from = strtotime($from);
$from = date("Y-m-d",$from);
$till = strtotime($till);
$till = date("Y-m-d",$till);
but still doesn't work, so any ideas?
Thank you.

Answer 1

First of all, your date column needs to be some kind of date datatype, like DATE or TIMESTAMP.
Second, you need to use valid dates for comparison. September 32 is no good. When MySQL tries to interpret that date it gets NULL. All comparisons between real values and NULLs come up false. So, you get an empty result set.
Third, BETWEEN is terrible for date comparison ; it often fouls up the end -- the last day -- of the range.
I suggest you use a query like this. Notice that the second date comparison to is the day after the end of the range you want.
$month = date(m);
$year = date(Y);
$day_start = '01';
$from = $year.'-'.$month.'-'.$day_start;
$result1 = $mysqli->query("SELECT COUNT(id)
FROM `dreams`
WHERE dream_state='dream'
AND date >= '$from'
AND date < '$from' + INTERVAL 1 MONTH");
$row1 = $result1->fetch_row();
$this_dream = $row1[0];

Answer 2

You include dashes in your dates but don't quote them as strings in the SQL. There are no date literals in SQL, so you have to represent dates as strings upon entry. Simply enclose them in single quotes to represent SQL value strings.
$result1 = $mysqli->query("SELECT COUNT(id) FROM `dreams` WHERE dream_state='dream'
AND date BETWEEN '$from' AND '$till'");
You also have an invalid date, as no month has 32 days. Computing the last day of each month seems a bit of an overkill here, so you're probably better off describing the first day of the next month, and using < to exclude it from the range.
A previous version of this answer suggested using numbers to describe dates instead of strings. While this works, it might be quite bad for performance, as #ypercube pointed out in a comment below.