php-mysql选择两个日期之间的最后插入记录（每个月）

Question

I have a table: box (id autoincrement, net_amount, created_at timestamp); I need to create a query in php mysql to select the last inserted record every month. Thus to get the net_amount at the end of every month. I am trying this simple query:

select * from box
 where box.created_at < 20055332516028

While the max created_at in my table is 2017-10-14 10:42:30, there is no records when I use the given query, I need to increase the number to get the records!!!

Answer 1

if i understand your problem your looking for this:-

SELECT b1.*
FROM box b1 LEFT JOIN box b2
ON (b1.name = b2.name AND b1.id < b2.id)
WHERE b1.created_at < PUT YOUR DATE  and b2.id IS NULL;

Hope it helps

Answer 2

20055332516028 is not a Unix timestamp. You need to get timestamp of the end of the previous month, something like this:

$date = new DateTime();
$date->setDate($date->format('Y'),$date->format('m'),1);
$date->setTime(0,0,0);
$date->sub(new DateInterval('PT1S'));
$endOfMonth = $date->getTimestamp();

and then use it in a query:

select * from box where box.created_at < unix_timestamp(?) order by box.created_at desc limit 1