我有一个按日期列出股票价格的表格，我想选择最接近多个日期的值。例如，给我最接近今天、1 个月前和 2 个月前的价格。我可以在单独的语句中完成，是否可以在单个语句中完成？
在下面，我想返回最接近 2/7、1/7 和 d 12/7 日期的第 1、2 和 6 行(最好使用 abs() 来这样做？) .
+---+------------+---------+----------------+----------------+----------------+
| d | quotedate | price | 2018-02-07diff | 2018-01-07diff | 2017-12-07diff |
+---+------------+---------+----------------+----------------+----------------+
| 1 | 2018-02-06 | 13.796 | -1 | 30 | 61 |
| 2 | 2018-01-09 | 14.1135 | -29 | 2 | 33 |
| 3 | 2018-01-02 | 13.822 | -36 | -5 | 26 |
| 4 | 2017-12-27 | 13.7365 | -42 | -11 | 20 |
| 5 | 2017-12-22 | 13.75 | -47 | -16 | 15 |
| 6 | 2017-12-04 | 13.589 | -65 | -34 | -3 |
| 7 | 2017-11-28 | 13.477 | -71 | -40 | -9 |
| 8 | 2017-10-31 | 13.214 | -99 | -68 | -37 |
+---+------------+---------+----------------+----------------+----------------+
我已经让它完成 1 行，但我希望能够同时完成所有 3 行吗？ fiddle :Here
最佳答案
select p1.id, p1.name,
DATE_FORMAT(p1.quote_date, "%Y-%m-%d") as quotedate,
p1.price,
DATEDIFF( p1.quote_date, '2018-02-07' ) as 'diff1',
DATEDIFF( p1.quote_date, '2018-01-07' ) as 'diff2',
DATEDIFF( p1.quote_date, '2017-12-07' ) as 'diff3'
from prices p1
left outer join (select id, name, quote_date, price,
DATEDIFF( quote_date, '2018-02-07' ) as 'diff1p2'
FROM prices) p2
on (p1.name = p2.name
AND DATEDIFF( p1.quote_date, '2018-02-07' )< diff1p2
AND DATEDIFF( p1.quote_date, '2018-02-07' ) <=0
)
WHERE p1.name = 'Stock1'
AND p2.id is null
union
select p1.id, p1.name,
DATE_FORMAT(p1.quote_date, "%Y-%m-%d") as quotedate,
p1.price,
DATEDIFF( p1.quote_date, '2018-02-07' ) as 'diff1',
DATEDIFF( p1.quote_date, '2018-01-07' ) as 'diff2',
DATEDIFF( p1.quote_date, '2017-12-07' ) as 'diff3'
from prices p1
left outer join (select id, name, quote_date, price,
DATEDIFF( quote_date, '2018-01-07' ) as 'diff1p2'
FROM prices) p2
on (p1.name = p2.name
AND DATEDIFF( p1.quote_date, '2018-01-07' )< diff1p2
AND DATEDIFF( p1.quote_date, '2018-01-07' ) <=0
您应该在 3 个查询之间使用联合，以便一次获得所有 3 行
关于MySQL在多列中选择最大值，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/48673836/