How to convert PHP and Mysql date and time (UNIX timestamp, formatted date)

Programmers who have written PHP+MySQL all know that there is a time difference. UNIX timestamps and formatted dates are two time representations that we often deal with. Unix timestamps are convenient to store and process, but not intuitive. Formatted dates are intuitive, but It is not as easy to process as Unix timestamps, so sometimes it is necessary to convert each other. Here are several conversion methods for mutual conversion.

1. Complete in MySQL

This method is converted in the MySQL query statement. The advantage is that it does not take up the parsing time of the PHP parser and is fast. The disadvantage is that it can only be used in database queries, which has limitations.

1. Function to convert UNIX timestamp to date: FROM_UNIXTIME()

General form: select FROM_UNIXTIME(1156219870);

2. Function to convert date to UNIX timestamp: UNIX_TIMESTAMP()

General form: Select UNIX_ TIMESTAMP ('2006-11-04 12:23:00′);

Example: mysql query the number of records on the day:

$sql=”select * from message Where DATE_FORMAT(FROM_UNIXTIME(chattime),'%Y-%m -%d') = DATE_FORMAT(NOW(),'%Y-%m-%d') order by id desc”;

Of course, you can also choose to convert in PHP. Let’s talk about conversion in PHP.

2. Complete it in PHP

This method completes the conversion in the PHP program. The advantage is that it can be converted regardless of whether the data is obtained by querying in the database, and the conversion range is not limited. The disadvantage is that it takes up the parsing time of the PHP parser. , the speed is relatively slow.

1. Use the function to convert UNIX timestamp to date: date()

General form: date('Y-m-d H:i:s', 1156219870);

2. Use the function to convert date to UNIX timestamp: strtotime( )

General form: strtotime('2010-03-24 08:15:42');