Datetime to date

1 PHP

echo date('Y-m-d', strtotime('2016-02-22 00:00:00'));
# 2016-02-22

echo date('Y-m-d', strtotime('2016-02-22 23:59:59'));
# 2016-02-22

2 SQL

2.1 MySQL

SELECT DATE('2016-02-22 00:00:00');
# 2016-02-22

SELECT DATE('2016-02-22 23:59:59');
# 2016-02-22