mysql query sql statement implementation principle and code within specified date_PHP tutorial

When designing the database tutorial, you must pay attention to the time field as int (11). In this way, what is saved in the database is a numeric date and time stamp. We can use the mktime function to find the timestamp of the current date and add or subtract. Let’s see an example below.
//One month

Copy code The code is as follows:

$lastMonth = mktime(date('h') ,date('i'),date('s'),date('m')-1,date('d'),date('y'));
$where .= ” dtime > $lastMonth”;

//Three months

Copy code The code is as follows:

$lastThreeMonth = mktime(date('h'),date('i'),date('s'),date('m')-3,date('d'),date('y'));
$where .= ” dtime > $lastThreeMonth”;

$sql = “select * from testtable ” .$where
/*
The principle is:
If it is a month, it is the current month minus the time you want to count. For example, if I want to query all the records in the database for the past three months from today, our statement is as follows: mktime(date('h' ),date('i'),date('s'),date('m')-3,date('d'),date('y'));
Within seven days:mktime(date ('h'),date('i'),date('s'),date('m'),date('d')-7,date('y'));
One hour Within:mktime(date('h')-1,date('i'),date('s'),date('m'),date('d'),date('y'));
The first day of last month: mktime(0,0,0,date('m')-1,01,date('Y'));
The last day of last month: mktime(0, 0,0,date('m'),0,date('y'));
The first day of this month: This is simple, which is 01;
The last day of this month: This is needed The date function has a parameter t, which is used to find the last day; such as: date('t')
Other methods are the same.

http://www.bkjia.com/PHPjc/326224.htmlwww.bkjia.comtruehttp: //www.bkjia.com/PHPjc/326224.htmlTechArticleWhen designing the database tutorial, you must pay attention to the time field as int (11). In this way, what is saved in the database is a numeric type. Date timestamp, we can use the mktime function to find the timestamp of the current date...