How to fix reading from till to date and time mysql? - php

Question

On my testpage i have 2 bootstrap datetime pickers.
When the user selects a start date/time and a end date/time and push the button the screen will be filled by data from sql database.
But i have trouble reading from the right time, date is no problem.
The code what i have is this.:
$date=$_POST['q'];
$date=explode(' ',$date);
echo "Date".': '.$date[0]."<br/>";
echo "Time".': '.$date[1]."<br/>";
$date1=$_POST['q1'];
$date1=explode(' ',$date1);
echo "Date".': '.$date1[0]."<br/>";
echo "Time".': '.$date1[1]."<br/>";
$a1 = $_POST['a1'];
$q = $date[0];
$q1 = $date1[0];
$q2 = $date[1];
$q3 = $date1[1];
$query = mysqli_query($conn,"SELECT *
FROM `metingen`
WHERE (Datum >= '$q' AND Datum <= '$q1')
and (Tijd >= '$q2' AND Tijd <= '$q3')
ORDER BY Id DESC");
Its not pritty but witout the tijd(time) its works great, with tijd(time) i miss data.
The date and time i split, as you can see , because the database what i want to use is not made by me, so the date is a seperated column and also time a seperated and both are also text.
if i echo the explode date/time a see.:
Date: 15-02-2019
Time: 01:00:32
Date: 16-02-2019
Time: 22:55:33
But the data what i get is from 15-2-2019 00:30:56 and till 15-2-2019 22:11:08
I don't see all the dates i miss dates from the 16 and i get dates before my start time.
I think i have something wrong in my sql rule but , i don't know what.
can somebody help me please.
This is my create and insert code of my table (i shorted it in a bit).:
CREATE TABLE `metingen` (
`Id` int(11) NOT NULL,
`Datum` varchar(255) DEFAULT NULL,
`Tijd` varchar(255) DEFAULT NULL,
) ENGINE=MyISAM DEFAULT CHARSET=utf8;
--
-- Gegevens worden geëxporteerd voor tabel `metingen`
--
INSERT INTO `metingen` (`Id`, `Datum`, `Tijd`) VALUES
(1, '17-1-2019', '10:31:39'),
(4, '18-1-2019', '10:30:01'),
(40, '28-1-2019', '23:59:42'),
(41, '28-1-2019', '00:50:12'),
(42, '29-1-2019', '02:00:42'),
(49, '29-1-2019', '06:22:53'),
(56, '5-2-2019', '19:35:02'),
(236, '13-2-2019', '13:58:43')
ALTER TABLE `metingen`
ADD KEY `Id` (`Id`);
ALTER TABLE `metingen`
MODIFY `Id` int(11) NOT NULL AUTO_INCREMENT, AUTO_INCREMENT=319;

Answer 1

You should not store date and time as separate fields in your database. You should just combine them into one datetime field in your database. You should then insert and compare such datetime values in one of the supported literal formats, such as YYYY-MM-DD H:m:s
Now back to your original situation. The problem is that you require the time condition also when the table's date is strictly between the two extreme dates (not equal to either of them). In that case there should be no constraint on the time part: all times would be OK on such days.
So here is how the SQL would look:
SELECT *
FROM metingen
WHERE ( Datum > '$q' OR ( Datum = '$q' AND Tijd >= '$q2' ) )
AND ( Datum < '$q1' OR ( Datum = '$q1' AND Tijd <= '$q3' ) )
ORDER BY Id DESC
But again, this is not the best practice.
If you have stored your dates as varchar (not as date), using the D-M-YYYY format, while your input is DD-MM-YYYY, then it becomes even more complex (and slow):
SELECT *
FROM metingen
WHERE ( STR_TO_DATE(Datum, '%d-%m-%Y') > STR_TO_DATE('$q', '%d-%m-%Y')
OR ( STR_TO_DATE(Datum, '%d-%m-%Y') = STR_TO_DATE('$q', '%d-%m-%Y')
AND Tijd >= '$q2' ) )
AND ( STR_TO_DATE(Datum, '%d-%m-%Y') < STR_TO_DATE('$q1', '%d-%m-%Y')
OR ( STR_TO_DATE(Datum, '%d-%m-%Y') = STR_TO_DATE('$q1', '%d-%m-%Y')
AND Tijd <= '$q3' ) )
ORDER BY Id DESC
Another issue is that you inject strings that are posted to the page, and so they are user-driven. This represents a SQL Injection vulnerabilty. Instead you should use prepared statements and pass the datetime strings as parameters.