is it safe to use 31 for "last day of the month" when comparing dates in MySQL

Question

I know this is not the perfect approach but is there a problem when comparing dates in MySQL and other DBs to just use Y-m-31 as the last day of the month?

For example

SELECT * FROM orders WHERE date > 2015-02-01 AND date < 2015-02-31

Answer 1

You can use the MySQL LAST_DAY() function for this:

SELECT * FROM orders WHERE date >= '2015-02-01' AND date <= LAST_DAY('2015-02-01')

(you probably also want >= and <= instead of excluding the first/last days of each month)