[英]MYSQL group_concat with and IF
有一個日期字段,我將從我的數據庫中獲取以下內容; PS以下是使用連接從日期表中獲取日期的更多查詢。
SELECT event,event_name,
GROUP_CONCAT(DATE_FORMAT(ed.date,'%b %e') ORDER BY ed.date SEPARATOR ',') as date2
FROM events ev
LEFT JOIN event_dates ed ON ev.eid=ed.eid
WHERE ev.yr='2013'
GROUP BY ev.eid
這會生成這個日期列表,占用大量空間。
May 16,May 23,May 30,Jun 6,Jun 20
我希望它看起來像
May 16,23,30,Jun 6,20
這是我試過的查詢。 但它不起作用,因為子查詢似乎不知道事件ID。 猜測我可能需要將其轉換為連接?
SELECT DISTINCT ev.event_id,
GROUP_CONCAT(DISTINCT DATE_FORMAT(race_date,'%a') ORDER BY race_date
SEPARATOR ', ') as date1,
(SELECT GROUP_CONCAT(dm) FROM
(SELECT CONCAT(
MONTHNAME(race_date),
' ',
GROUP_CONCAT(DAY(race_date) ORDER BY race_date)
) as dm
FROM event_dates ed1 WHERE ed1.event_id=ev.event_id
GROUP BY MONTH(race_date))as t) as date2
FROM events ev
JOIN event_dates ed ON ev.event_id = ed.event_id AND ev.race_year = ed.race_year
GROUP BY event_id
SELECT GROUP_CONCAT(d) FROM (
SELECT CONCAT(
MONTHNAME(date),
' ',
GROUP_CONCAT(DAY(date) ORDER BY date)
) AS d
FROM my_table
GROUP BY MONTH(date)
) t
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