[英]Find the day of every nth week of a month (e.g. find Friday of second week of next month knowing Friday the second week of this month)
[英]MySQL - Compare data from months by day of week - e.g. sessions on first Saturday of each month
當客戶來參加會議時,我有一張桌子錄音。 我想創建一個圖表來比較去年完成的會話數。 我想出了如何使用以下 sql 獲取每個月的結果:
SELECT
DAY(`SessionDate`) as month_day,
SUM(if(MONTH(SessionDate) = 1, 1, 0)) AS Jan,
SUM(if(MONTH(SessionDate) = 2, 1, 0)) AS Feb,
SUM(if(MONTH(SessionDate) = 3, 1, 0)) AS Mar,
SUM(if(MONTH(SessionDate) = 4, 1, 0)) AS Apr,
SUM(if(MONTH(SessionDate) = 5, 1, 0)) AS May,
SUM(if(MONTH(SessionDate) = 6, 1, 0)) AS Jun,
SUM(if(MONTH(SessionDate) = 7, 1, 0)) AS Jul,
SUM(if(MONTH(SessionDate) = 8, 1, 0)) AS Aug,
SUM(if(MONTH(SessionDate) = 9, 1, 0)) AS Sep,
SUM(if(MONTH(SessionDate) = 10, 1, 0)) AS 'Oct',
SUM(if(MONTH(SessionDate) = 11, 1, 0)) AS 'Nov',
SUM(if(MONTH(SessionDate) = 12, 1, 0)) AS 'Dec'
FROM sessions
WHERE
`SessionDate` >= NOW()-Interval 12 MONTH
GROUP BY DAY(`SessionDate`)
ORDER BY DAY(SessionDate)
結果如下所示:
------------------------------...
|month_day | Jan | Feb | Mar |...
------------------------------...
| 1| 1 | 2 | 0 |...
| 2| 2 | 3 | 1 |...
| 3| 0 | 4 | 1 |...
| 4| 0 | 4 | 2 |...
| 5| 4 | 3 | 3 |...
| 6| 2 | 1 | 4 |...
| 7| 2 | 0 | 4 |...
| 8| 1 | 2 | 4 |...
...
然而,這比較了每年 1 月 1 日到 2 月 1 日到 3 月 1 日……我想查看和比較的是每個月的第一個星期一有多少個會話……
假設 1. Jan 是星期五,1. Feb 是星期二,Mar 是星期三,那么我的結果應該是這樣的:
-----------------------------...
|weekday | Jan | Feb | Mar |...
-----------------------------...
| 1st Mon | | | |...
| 1st Tue | | 2 | |...
| 1st Wed | | 3 | 1 |...
| 1st Thu | | 4 | 0 |...
| 1st Fri | 1 | 4 | 1 |...
| 1st Sat | 2 | 3 | 1 |...
| 1st Sun | 0 | 1 | 2 |...
| 2nd Mon | 0 | 0 | 3 |...
| 2nd Tue | 4 | 2 | 4 |...
| 2nd Wed | 1 | 2 | 4 |...
| 2nd Thu | 1 | 2 | 4 |...
| 2nd Fri | 3 | 3 | 2 |...
| 2nd Sat | 4 | 1 | 0 |...
| 2nd Sun | 2 | 1 | 0 |...
| 3rd Mon | 0 | 0 | 1 |...
| 3rd Tue | 1 | 0 | 4 |...
... etc
換句話說,圖表將顯示哪些工作日是受歡迎的(例如,每個月的第一個星期六比第三個星期六有更多的會話)我用 php 和 Google 靜態圖表繪制圖表,所以沒問題。 讓每月數據抵消以使工作日在同一行中是我無法弄清楚的。 希望我的問題有意義。 我是一名業余編碼員,也是 stackoverflow 的新手,因此我們將不勝感激。
這是我想出的解決方案。 它看起來有點笨重但有效。 我仍然願意接受更好的解決方案。
SELECT
a.m AS CalPos, /* Calendar Position (not date)
e.g. if the month starts on a Tues,
the 1st would display in CalPos 2 */
COALESCE(b.Jan,0) AS 'Jan',
COALESCE(b.Feb,0) AS 'Feb',
COALESCE(b.Mar,0) AS 'Mar',
COALESCE(b.Apr,0) AS 'Apr',
COALESCE(b.May,0) AS 'May',
COALESCE(b.Jun,0) AS 'Jun',
COALESCE(b.Jul,0) AS 'Jul',
COALESCE(b.Aug,0) AS 'Aug',
COALESCE(b.Sep,0) AS 'Sep',
COALESCE(b.Oct,0) AS 'Oct',
COALESCE(b.Nov,0) AS 'Nov',
COALESCE(b.Dec,0) AS 'Dec'
FROM (
SELECT 1 AS m
UNION SELECT 2 AS m
UNION SELECT 3 AS m
UNION SELECT 4 AS m
UNION SELECT 5 AS m
UNION SELECT 6 AS m
UNION SELECT 7 AS m
UNION SELECT 8 AS m
UNION SELECT 9 AS m
UNION SELECT 10 AS m
UNION SELECT 11 AS m
UNION SELECT 12 AS m
UNION SELECT 13 AS m
UNION SELECT 14 AS m
UNION SELECT 15 AS m
UNION SELECT 16 AS m
UNION SELECT 17 AS m
UNION SELECT 18 AS m
UNION SELECT 19 AS m
UNION SELECT 20 AS m
UNION SELECT 21 AS m
UNION SELECT 22 AS m
UNION SELECT 23 AS m
UNION SELECT 24 AS m
UNION SELECT 25 AS m
UNION SELECT 26 AS m
UNION SELECT 27 AS m
UNION SELECT 28 AS m
UNION SELECT 29 AS m
UNION SELECT 30 AS m
UNION SELECT 31 AS m
UNION SELECT 32 AS m
UNION SELECT 33 AS m
UNION SELECT 34 AS m
UNION SELECT 35 AS m
UNION SELECT 36 AS m
UNION SELECT 37 AS m
UNION SELECT 38 AS m
) AS a
LEFT JOIN
( SELECT
CASE
WHEN
(7 - MOD((9-DAYOFWEEK(CAST(DATE_SUB(CONCAT(DATE_FORMAT(SessionDate,'%Y-%m-'),'01'), INTERVAL 7 DAY) AS DATE) )),7)) = 7
THEN
(DAY(`SessionDate`)+( MOD((9-DAYOFWEEK(CAST(DATE_SUB(CONCAT(DATE_FORMAT(SessionDate,'%Y-%m-'),'01'), INTERVAL 7 DAY) AS DATE) )),7)))
ELSE
(DAY(`SessionDate`)+(7 - MOD((9-DAYOFWEEK(CAST(DATE_SUB(CONCAT(DATE_FORMAT(SessionDate,'%Y-%m-'),'01'), INTERVAL 7 DAY) AS DATE) )),7)))
END AS CalPos,
SUM(IF(MONTH(SessionDate) = 1, 1, 0)) AS 'Jan',
SUM(IF(MONTH(SessionDate) = 2, 1, 0)) AS 'Feb',
SUM(IF(MONTH(SessionDate) = 3, 1, 0)) AS 'Mar',
SUM(IF(MONTH(SessionDate) = 4, 1, 0)) AS 'Apr',
SUM(IF(MONTH(SessionDate) = 5, 1, 0)) AS 'May',
SUM(IF(MONTH(SessionDate) = 6, 1, 0)) AS 'Jun',
SUM(IF(MONTH(SessionDate) = 7, 1, 0)) AS 'Jul',
SUM(IF(MONTH(SessionDate) = 8, 1, 0)) AS 'Aug',
SUM(IF(MONTH(SessionDate) = 9, 1, 0)) AS 'Sep',
SUM(IF(MONTH(SessionDate) = 10, 1, 0)) AS 'Oct',
SUM(IF(MONTH(SessionDate) = 11, 1, 0)) AS 'Nov',
SUM(IF(MONTH(SessionDate) = 12, 1, 0)) AS 'Dec'
FROM sessions
WHERE
`SessionDate` >= NOW() - INTERVAL 12 MONTH
GROUP BY CalPos
ORDER BY CalPos
) AS b
ON a.m = b.CalPos
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