MySql：从年和月创建日期时间

Question

I have the following query:

SELECT count(*) as 'count' 
    FROM myTable 
    WHERE myDateTime >= DATE1 AND myDateTime < DATE2

- myDateTime is of type datetime ( 2013-01-30 08:48:13 ) in myTable .
- DATE1 and DATE2 should be created as datetime also so I could compare them, like this:

- DATE1 should to be created from year (eg 2013) and month (eg 01) parameters, and the day should always be 01 (the first day of the month)
- DATE2 should be same as DATE1 with an added month. (if DATE1 is 2013-01-01 00:00:00 then DATE2 should be 2013-02-01 00:00:00 )

Answer 1

You can create the date as a number and then convert it to a date:

where myDateTime >= date(@year * 10000 + @month * 100 + 1) and
      myDateTime < date_add(date(@year * 10000 + @month * 100 + 1), interval 1 month)