Generating Reports with SQL Date Handling - Hacking the Hack: The Last Thursday of the Month
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You can use a similar technique to calculate the last Thursday of the month. Just find the first Thursday of next month and subtract seven days.
The formula for the offset for the first Thursday of the month beginning withmonthdateis:
(12-DAYOFWEEK(monthdate) ) % 7
You should subtract from 12 because Thursday is represented by 5 and 5 + 7 = 12.
The query to get the first day of next month is:
mysql> SELECT monthdate AS first_day_of_month
-> ,DATE_ADD(monthdate,INTERVAL 1 MONTH)
-> AS first_day_of_next_month
-> FROM monthdates;
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first_day_of_month first_day_of_next_month |
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2007-04-01 | 2007-05-01 | |
2007-05-01 | 2007-06-01 | |
2007-06-01 | 2007-07-01 | |
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You can use this result to find the first Thursday of next month and subtract 7 to get the last Thursday of this month:
mysql> SELECT first_day_of_month
-> ,DATE_ADD(first_day_of_next_month
-> ,INTERVAL
-> ((12 - DAYOFWEEK(first_day_of_next_month)) % 7)
-> - 7 DAY) AS last_thursday_of_month
-> FROM
-> (SELECT monthdate AS first_day_of_month
-> ,DATE_ADD(monthdate,INTERVAL 1 MONTH)
-> AS first_day_of_next_month
-> FROM monthdates) t;
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first_day_of_month last_thursday_of_month |
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2007-04-01 | 2007-04-26 | |
2007-05-01 | 2007-05-31 | |
2007-06-01 | 2007-06-28 | |
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See Also
“Generate a Calendar” [Hack #87]—Rudy Limeback
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 This article is excerpted from chapter four of the book SQL Hacks, written by Andrew Cumming and Gordon Russell (O'Reilly, 2006; ISBN: 0596527993). Check it out today at your favorite bookstore. Buy this book now.
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