asked on

MYSQL - How to get 1st, 2nd, 3rd etc... Monday, Tuesday, Wednesda, etc ... date in a month

Having trouble finding the 1st, 2nd, whatever day in a month.
I know the month and year. Say... Sept. 2008
I want to know what is the Date of First Monday in that month. or Second Friday, etc.
I have seen some other functions in pSQL and Oracle but not MySQL. I have MySQL version 5.x

dansoto

Do you want to find a particular record for the first day ?

Bob-Villa

ASKER

i want to know the date of the first monday in september of 2008 returned in MYSQL format. not the date of an actual record.

ASKER CERTIFIED SOLUTION

pssandhu

membership

This solution is only available to members.

To access this solution, you must be a member of Experts Exchange.

Start Free Trial

_agx_

(No points please. This is just a translation)

Here is a rough translation of pssandhu's function into MySQL. Watch out for line wrapping

delimiter //
 
CREATE FUNCTION fn_GetWeekdayDate (      
TheDate  Datetime,
DayName  varchar(10),
DayNum   Tinyint
)
RETURNS Datetime
BEGIN
  DECLARE InitialDate     Datetime;
  DECLARE ReturnDate      Datetime;
  DECLARE Dow int;
    
  SET InitialDate = 
	CASE WHEN Date_Format(TheDate, '%W') = DayName THEN TheDate
             WHEN Date_Format(Date_Add(TheDate, INTERVAL 1 DAY), '%W') = DayName THEN Date_Add(TheDate, INTERVAL 1 DAY)
             WHEN Date_Format(Date_Add(TheDate, INTERVAL 2 DAY), '%W') = DayName THEN Date_Add(TheDate, INTERVAL 2 DAY)
             WHEN Date_Format(Date_Add(TheDate, INTERVAL 3 DAY), '%W') = DayName THEN Date_Add(TheDate, INTERVAL 3 DAY)
             WHEN Date_Format(Date_Add(TheDate, INTERVAL 4 DAY), '%W') = DayName THEN Date_Add(TheDate, INTERVAL 4 DAY)
             WHEN Date_Format(Date_Add(TheDate, INTERVAL 5 DAY), '%W') = DayName THEN Date_Add(TheDate, INTERVAL 5 DAY)
             WHEN Date_Format(Date_Add(TheDate, INTERVAL 6 DAY), '%W') = DayName THEN Date_Add(TheDate, INTERVAL 6 DAY)
             ELSE TheDate
        END;
 
  SET ReturnDate = CASE WHEN DayNum IS NULL or DayNum IN (0,1) Then InitialDate
                        ELSE Date_Add(InitialDate, INTERVAL (7*(DayNum-1)) DAY)
                   END;
 
  /* uncomment this if you want to return null instead 
     of allowing crossover months
 
  SET ReturnDate = CASE WHEN Month(TheDate) = Month(ReturnDate) THEN ReturnDate 
   			ELSE NULL 
		   END;
  */
 
  RETURN ReturnDate;
END
//
 
delimiter ;
 
SELECT fn_GetWeekdayDate('2008-09-01', 'MONDAY', 1);

Open in new window

_agx_

What was inadequate about pssandhu's suggestion? IMO it did exactly what the asker requested.

I don't want any points for it, but did they try the translated version?

Bob-Villa

ASKER

pssandhu provided sql code that did not work with mysql. agx provided a rough translation that needed some work. I was looking for some built-in function, or an advanced query that I was unfamiliar with, perhaps I didn't ask clearly. I was able to accomplish the same thing (in the 43 lines above) in 2 lines of perl code. If I were another user searching for the same solution I don't feel the answers given here would have been a great solution. Didn't mean to offend anyone, I was just trying to clean up my 2 open questions. Please don't respond with any additional comments I don't have time to debate this issue. I pay my $10 a month to find quick answers in a pinch, not to debate the quality of the answers given by other members.

_agx_

No need for debate. No further suggestions were offered because no other comments were made until now. For future reference if a suggestion doesn't meet your needs, for whatever the reason, feel free to ask for alternatives :) In addition, be sure to provide complete details about your environment so responders will know what options are available to you.