How to set up a WHILE loop with IF statement in MySQL? - mysql

Question

I would like to create a stored routine for MySQL that figures out the number of business or working days for a month (Working Days are Monday thru Friday).
It's a syntax error however I don't know what the syntax error is. All it tells me is:
1064 - You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use
near 'WHILE(#daycount < #totaldays) DO IF (WEEKDAY(#checkweekday) < 6)
THEN ' at line 2
My Syntax Error is in the following:
WHILE(#daycount < #totaldays) DO
IF (WEEKDAY(#checkweekday) < 6) THEN
My Code:
SELECT MONTH(CURDATE()) INTO #curmonth;
SELECT MONTHNAME(CURDATE()) INTO #curmonthname;
SELECT DAY(LAST_DAY(CURDATE())) INTO #totaldays;
SELECT FIRST_DAY(CURDATE()) INTO #checkweekday;
SELECT DAY(#checkweekday) INTO #checkday;
SET #daycount = 0;
SET #workdays = 0;
BEGIN
WHILE(#daycount < #totaldays) DO
IF (WEEKDAY(#checkweekday) < 6) THEN
SET #workdays = #workdays+1;
END IF;
SET #daycount = #daycount+1;
SELECT ADDDATE('#checkweekday', INTERVAL 1 DAY) INTO #checkweekday;
END WHILE;
END;
SELECT #workdays;
Is someone able to assist?
UPDATE
I receive the same error with the following bit of code so it probably has something to do with this:
SET #workdays = 0;
IF (WEEKDAY('2013-06-13') < 6) THEN
SET #workdays = #workdays+1;
END IF;
SELECT #workdays;

Answer 1

I have discovered that you cannot have conditionals outside of the stored procedure in mysql. This is why the syntax error. As soon as I put the code that I needed between
BEGIN
SELECT MONTH(CURDATE()) INTO #curmonth;
SELECT MONTHNAME(CURDATE()) INTO #curmonthname;
SELECT DAY(LAST_DAY(CURDATE())) INTO #totaldays;
SELECT FIRST_DAY(CURDATE()) INTO #checkweekday;
SELECT DAY(#checkweekday) INTO #checkday;
SET #daycount = 0;
SET #workdays = 0;
WHILE(#daycount < #totaldays) DO
IF (WEEKDAY(#checkweekday) < 5) THEN
SET #workdays = #workdays+1;
END IF;
SET #daycount = #daycount+1;
SELECT ADDDATE(#checkweekday, INTERVAL 1 DAY) INTO #checkweekday;
END WHILE;
END
Just for others:
If you are not sure how to create a routine in phpmyadmin you can put this in the SQL query
delimiter ;;
drop procedure if exists test2;;
create procedure test2()
begin
select ‘Hello World’;
end
;;
Run the query. This will create a stored procedure or stored routine named test2. Now go to the routines tab and edit the stored procedure to be what you want. I also suggest reading http://net.tutsplus.com/tutorials/an-introduction-to-stored-procedures/ if you are beginning with stored procedures.
The first_day function you need is:
How to get first day of every corresponding month in mysql?
Showing the Procedure is working
Simply add the following line below END WHILE and above END
SELECT #curmonth,#curmonthname,#totaldays,#daycount,#workdays,#checkweekday,#checkday;
Then use the following code in the SQL Query Window.
call test2 /* or whatever you changed the name of the stored procedure to */
NOTE: If you use this please keep in mind that this code does not take in to account nationally observed holidays (or any holidays for that matter).