SQL date logic to fetch the values - mysql

Question

Need SQL logic
If i enter sys date as 15th it has to fetch the values from 1-15th.
if i enter date as following month 2nd it has to fetch from 15th to
2nd.
Example
Sys date April 15th - April 1 to April 15th date values needs to be fetch.
Sys date May 2nd - April 15th to May 2nd date values needs to be fetch.
Please suggest

Answer 1

So as a general methodology you'd need a function to return the day number in the month, and two case statements to each return a particular date as a boundary. Date arithmetic is used to convert the system date to the upper and lower boundaries required, so on Oracle you'd use Trunc(sysdate,'mm') and add_months(...,n) and add days on as integers.
Date functions are here: http://docs.oracle.com/cd/B28359_01/server.111/b28286/functions001.htm
Can't help you with MySQL functions -- doubtless they're documented somewhere.
you'll end up with ...
date_col > case <function on sysdate>
when < 15 then <function for lower bound case 1>
when < 15 then <function for lower bound case 2>
end and
date_col < case <function on sysdate>
when < 15 then <function for upper bound case 1>
when < 15 then <function for upper bound case 2>
end and

Answer 2

I would recommend using DAYOFWEEK() and MONTH() functions to determine the start and end dates of the query.
SET #day = DAYOFMONTH(<date entered>)
SET #month = MONTH(<date entered>)
IF #month > MONTH(NOW()) AND #day = 2 THEN
SET #start_date = DATE_SUB(<date entered>, INTERVAL 1 MONTH) + INTERVAL 13 DAY
SET #end_date = <date entered>
ELSEIF #month = MONTH(NOW()) AND #day = 15 THEN
SET #start_date = DATE_SUB(<date entered>, INTERVAL 14 DAY)
SET #end_date = <date entered>
END IF;
SELECT * FROM myTable WHERE myDate BETWEEN #start_date AND #end_date