How to get first day of every corresponding month in mysql?

Question

I want to get first day of every corresponding month of current year. For example, if user selects \'2010-06-15\', query demands to run from \'2010-06-01\' instead of \'2010

Answer 1

There is actually a straightforward solution since the first day of the month is simply today - (day_of_month_in_today - 1):

select now() - interval (day(now())-1) day

Contrast that with the other methods which are extremely roundabout and indirect.

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Also, since we are not interested in the time component, curdate() is a better (and faster) function than now(). We can also take advantage of subdate()'s 2-arity overload since that is more performant than using interval. So a better solution is:

select subdate(curdate(), (day(curdate())-1))