Search between dates (date as VARCHAR) - php

Question

I have several dates stored as varchar in the following format: 01-01-2012
I want to search between dates, but sadly it isn't working as I expected. I looked for other threads which have the same question (kinda), but the answers provided there didn't work for me.
Here is my code:
$fromday = $_POST['fromday'];
$frommonth = $_POST['frommonth'];
$fromyear = $_POST['fromyear'];
$tillday = $_POST['tillday'];
$tillmonth = $_POST['tillmonth'];
$tillyear = $_POST['tillyear'];
$vanaf = "$fromday-$frommonth-$fromyear";
$tot = "$tillday-$tillmonth-$tillyear";
// zoeken
$sel = "SELECT * FROM bestelling WHERE verzenddatum >= '$vanaf' AND verzenddatum <= '$tot'";
$dosel = mysql_query($sel) or die(mysql_error());
while($row = mysql_fetch_assoc($dosel))
{
$datum = $row['verzenddatum'];
echo $datum;
}
Please let me know what I'm doing wrong!

Answer 1

It is not returning any rows because the query is not doing the comparison on valid DATE or DATETIME fields. You should be storing the dates as a DATE type, but what you could do is this:
// Switch the order of date elements:
$vanaf = mysql_real_escape_string("$fromyear-$frommonth-$fromday");
$tot = mysql_real_escape_string("$tillyear-$tillmonth-$tillday");
$sel = "SELECT * FROM bestelling WHERE STR_TO_DATE(verzenddatum, '%d-%m-%Y') BETWEEN '$vanaf' AND 'tot'";
The mysql_real_escape_string() function simply reduces the risk of SQL injection, which is what your original code was vulnerable to.
The MySQL function STR_TO_DATE() converts a string to a valid MySQLDATE type. %d-%m-%Y is the format you have in your varchar string currently, but STR_TO_DATE converts it to '%Y-%m-%d' which MySQL can then use to make range comparisons.
Also, I'm using the BETWEEN syntax in the SQL as it is the same thing as val >= val1 AND val <= val2. It's just clearer and simpler: val BETWEEN val1 AND val2.

Answer 2

You need to store the dates as either DATE field types or DATETIME field types. Migrate your database with a script (shouldn't be too hard on a small DB: Backup your table, convert all of your dates to the proper format, change the schema and then re-insert your data. Restore your backup if it explodes.) After fixing this, everything will work as expected.

Answer 3

I would strongly recommend that you fix this by converting the fields to proper DATE fields now and take the pain, rather than waiting until the inevitable performance problems that this approach will incur arise. If you cannot, try this:
$fromday = $_POST['fromday'];
$frommonth = $_POST['frommonth'];
$fromyear = $_POST['fromyear'];
$tillday = $_POST['tillday'];
$tillmonth = $_POST['tillmonth'];
$tillyear = $_POST['tillyear'];
$sel = "SELECT * FROM bestelling WHERE SUBSTRING(verzenddatum, 7, 4) BETWEEN '$fromyear' AND '$tillyear' AND SUBSTRING(verzenddatum, 4, 2) BETWEEN '$frommonth' AND '$tillmonth' AND SUBSTRING(verzenddatum, 1, 2) BETWEEN '$fromday' AND '$tillday';"
(The hope here is that if a record's date lies outside the "from year" and "to year", the MySQL query optimiser will notice this and bail out early)

Answer 4

MySQL's standard date format is 'year-month-day' try this $vanaf = "$fromyear-$frommonth-$fromday"; and do the same for $tot. Try that and see if it works.

Answer 5

Some theory:
$startdate = sprinf('%04d-%02d-%02d', $year, $month, $day);
$enddate = sprinf('%04d-%02d-%02d', $year, $month, $day);
$query = "SELECT * FROM orders WHERE date BETWEEN '{$startdate}' AND '{$enddate}'";
My tipp: Invest some time in PDO and prepared statements. Dont use mysql_ functions anymore.

Answer 6

Since you are using PHP, you can set your data type in MySQL to INT (Integer) and use UNIX Timestamps for your dates. This is a good way to search for greater than and less than values.
You can use something like:
$fromday = strtotime($_POST['fromday']);

Answer 7

Change Only Mysql query it's Working.
select * from Your_table_name
where STR_TO_DATE( "your_date_field" , '%d/%m/%Y' )
BETWEEN STR_TO_DATE("your_first_date", '%d/%m/%Y')
AND STR_TO_DATE("your_second_date", '%d/%m/%Y')