mysqli prepared statements with between clause - php

Question

My question is similar to [this][1] but the solution provided there doesn't work for me.
I have a DB and I have one column called birth that contains a date in the format year-day-month 00:00:00. Now I want to extract from the DB all the records which birth is between two dates.
The birth value has been inserted in the DB with this code
$date = $day . "-" . $month. "-" . $year;
$a = strptime($date, '%d-%m-%Y');
$DB_date = date('Y-m-d H:i:s',mktime(0, 0, 0, $a['tm_mon']+1, $a['tm_mday'], $a['tm_year']+1900));
To extract the dates I am using this code:
$stmt = $conn->prepare('SELECT * FROM database WHERE `birth` BETWEEN ? AND ?');
$start_date = '1990-01-01';
$stop_date = '1995-01-01';
$stmt->bind_param('ss',$start_date,$stop_date);
$stmt->execute();
$result = $stmt->get_result();
but it doesn't find anything so $result->num_rows is equal to 0 and it doesn't give any errors so the problem must be in the comparison of the dates.

Answer 1

Birth column format is y-d-m hour min sec. But in your where clause you are ignoring hour minute second factor.
Replace:
$start_date = '1990-01-01';
$stop_date = '1995-01-01';
With this:
$start_date = '1990-01-01 00:00:00';
$stop_date = '1995-01-01 00:00:00';
Kindly try it and let me know if it works

Answer 2

I found the solution
The code in my question works if the data type of the column in the DB is datetime and you also need to make sure that $start_date is older than $stop_date. I still wonder though why it didn't work with the date data type.

Answer 3

I had the same issue. I found another thread with the same problem (not sure how to duplicate this thread) here
However just to sum up,
They managed to get the desired results by bracketing the question marks for the params.
$stmt = $conn->prepare('SELECT * FROM database WHERE `birth` BETWEEN (?) AND (?)');
$start_date = '1990-01-01';
$stop_date = '1995-01-01';
$stmt->bind_param('ss',$start_date,$stop_date);
$stmt->execute();
$result = $stmt->get_result();
Hope this helps.