PHP删除MySQL记录超过3天的记录

Question

I have the following at the top of every page so when the website is loaded by anyone PHP deletes any record in a specific database table that is older than 3 days.

$conn = getConnected("oversizeBoard");
mysqli_query($conn, "DELETE FROM postedLoads WHERE date < DATE_SUB(DATE('m-d-Y'), INTERVAL 3 DAY");

The problem is nothing is being deleted.

The data type for my date column is varchar(20) and when I insert a date into MySQL it is entered using date("mdY") . The name of my date field is date . So it appears that the above query would be correct, but I have done something wrong, and I am not certain as to what since every example I've looked at has basically looked the same except they used now() instead of date() but I use a specific date format so I can't use now() in my query.

What have I done wrong?

I even tried putting it into a function:

function deleteOversizeRows() {
$conn = getConnected("oversizeBoard");
mysqli_query($conn, "DELETE FROM postedLoads WHERE date < DATE_SUB(DATE('m-d-Y'), INTERVAL 3 DAY");
}
deleteOversizeRows();

Answer 1

Try to provide date by calculating first and then use it in query like below

$date = date("m-d-Y", strtotime('-3 day'));
$conn = getConnected("oversizeBoard");
mysqli_query($conn, "DELETE FROM postedLoads WHERE date < '".$date."');

It might help you. If need any other solution or help, do ask here.

Answer 2

Use MySQL function TIMESTAMPDIFF(unit,datetime_expr1,datetime_expr2);

Function calculates difference between two dates and returns output based on the unit parameter passed .

Try this:

DELETE FROM postedLoads WHERE TIMESTAMPDIFF('DAY',date,now())<3;

For detailed info of function: http://www.w3resource.com/mysql/date-and-time-functions/mysql-timestampdiff-function.php