Question

HI 我有一个表listsing_prices（id，listing_id，day_from，day_to，price）我需要在mysql中计算假期的总费用，因为我需要按总费用对结果进行排序。

EX：

VALUES IN TABLE
1  6   2011-04-27   2011-04-30   55,00
2  6   2011-05-01   2011-05-02   60,00
3  6   2011-05-03   2011-05-15   65,00

假期从2011-04-28到2011-05-05总费用= 480

Answer 1

select count(price) from listing_prices where day_from >= '2011-04-28' and day_to <= '2011-05-05'

Answer 2

-- This will provide a list of ids along with how many days fall between the two
SELECT a.id, DATEDIFF(DAYS, CASE WHEN day_from < '2011-04-28' THEN '2011-04-28' ELSE day_from END CASE, day_to) AS DayCount
FROM listing_prices a
WHERE '2011-04-28' BETWEEN a.date_from AND a.date_to
    AND a.date_to <= '2011-05-05'

-- Based on the previous query, sum the number of days within the range
SELECT SUM( a.price * b.DayCount ) AS Total
FROM listing_prices a
JOIN ( SELECT a.id, DATEDIFF(DAYS, CASE WHEN day_from < '2011-04-28' THEN '2011-04-28' ELSE day_from END CASE, day_to) AS DayCount
FROM listing_prices a
WHERE '2011-04-28' BETWEEN a.date_from AND a.date_to
    AND a.date_to <= '2011-05-05'

）b ON a.id = b.id

请注意，这是未经测试的...顶部的查询我认为应该可以工作，但如果没有，可以修改它，以便它确实有效（获取每个范围内的天数）然后字面上复制并粘贴到第二个查询的子查询中。第二个查询是您实际使用的查询。

Answer 3

如果不创建实际表来表示从开始日期到结束日期的每一天，您可以使用mysql查询变量。第一个查询可以加入到任何表中，只要它与您在周末期间所关注的天数一样多...在这种情况下，从4月28日到5月5日为止8天。通过做笛卡尔并限制为8从本质上讲，从2011/04/28（您的开始日期）开始，每天创建一个包含一条记录的临时结果集。

然后，这会返回到与日期相匹配的定价表，并将总成本的匹配价格相加...

select  
        sum( pt.price ) as TotalCosts
    from 
        ( SELECT 
                 @r:= date_add(@r, interval 1 day ) CalendarDate
            FROM 
                 (select @r := STR_TO_DATE('2011/04/28', '%Y/%m/%d')) vars,
                AnyTableWithAtLeast8ays limit 8 ) JustDates,
        PricesTable pt
    where
        JustDates.CalendarDate between pt.date_from and pt.date_to

Mysql查询计算总成本

3 个答案: