how can I delete date in this table?

Question

I have table like this

create table tbl_1(
  year int,
  month int, 
 day int
)

insert into tbl_1 values(2009,  11, 30)
insert into tbl_1 values(2010,   3,  4)
insert into tbl_1 values(2011,   5, 13)
insert into tbl_1 values(20011, 12, 24)

I want to delete date from 2009-11-30 until 2011-5-13, but I can't because all of columns are int and I can't use this query :

delete from tbl_1 
 where year >=2009 
   and year<=2011 
   and month >=11 
   and month <=5 
   and day >=30 
   and day <=13

..because: 1 < month < 12 and 1 < day < 30

I know that this is terrible mistake.

I have many table that use this way for save date , please help me I don't have time to delete and recreate all of them.

Answer 1

You could do it like this:

DELETE FROM tbl_1 
WHERE (year * 10000 + month * 100 + day) BETWEEN 20091130 AND 20110513

I haven't tested this. I would recommend testing it first on a test system before running it on your production data so that you don't accidentally delete the wrong data.