我试图显示我正在建造的商店的运费,数据库中有三个表 1 用于服务,即皇家邮政、承运人......,一个用于乐队,即。英国、欧洲、全球 1 等.. 一个用于收费(数量 = 重量)
我有一个包含三个表的数据库,当它们连接时形成以下
+------------------+-----+-----------+-------+---------+---------------+----------+-------+-------------+
| name | qty | serviceID | basis | bandID | initial_charge | chargeID | price | total_price |
+------------------+-----+-----------+-------+---------+---------------+----------+-------+-------------+
| Collect in store | 0 | 3 | | 1 | 3 | 0.00 | 2 | 0.00 |
| Royal mail | 0 | 1 | 2 | 4 | 2.00 | 3 | 0.00 | 2.00 |
| Royal mail | 1 | 1 | 2 | 4 | 2.00 | 4 | 1.00 | 3.00 |
| APC | 0 | 2 | 1 | 1 | 0.00 | 6 | 5.95 | 5.95 |
+------------------+-----+-----------+-------+---------+---------------+----------+-------+-------------+
基本上我想做的是(如您所见)皇家邮政有两个条目,因为连接表中有多个条目。我想做的是显示两个皇家邮件条目中最高的一个(我最初试图按 service_id 分组),同时还维护具有不同服务 ID 的其他两个服务
任何帮助都会很棒,因为这让我发疯。我觉得我已经尝试了每一种组合!
在下面的示例中,物品的数量(重量)为 3kg
SELECT
`service`.`name`,
`charge`.`qty`,
`service`.`serviceID`,
`band`.`bandID`,
`band`.`initial_charge`,
`charge`.`chargeID`,
`charge`.`price`,
`band`.`initial_charge` + `charge`.`price` AS `total_price`
FROM
`delivery_band` AS `band`
LEFT JOIN
`delivery_charge` AS `charge`
ON
`charge`.`bandID` = `band`.`bandID`
AND
`charge`.`qty` < '3'
LEFT JOIN
`delivery_service` AS `service`
ON
`service`.`serviceID` = `band`.`serviceID`
WHERE
FIND_IN_SET( '225', `band`.`accepted_countries` )
AND
(
`band`.`min_qty` >= '3'
OR
`band`.`min_qty` = '0'
)
AND
(
`band`.`max_qty` <= '3'
OR
`band`.`max_qty` = '0'
)
送货服务
+-----------+------------------+
| serviceID | name |
+-----------+------------------+
| 1 | Royal mail |
| 2 | APC |
| 3 | Collect in store |
+-----------+------------------+
传送带
+--------+-----------+-----------------+----------------+---------+---------+-------------------------------------------------------+
| bandID | serviceID | name | initial_charge | min_qty | max_qty | accepted_countries |
+--------+-----------+-----------------+----------------+---------+---------+-------------------------------------------------------+
| 1 | 2 | UK Mainland | 0.00 | 0 | 0 | 225 |
| 2 | 2 | UK Offshore | 14.00 | 0 | 0 | 240 |
| 3 | 3 | Bradford Store | 0.00 | 0 | 0 | 225 |
| 4 | 1 | UK | 2.00 | 0 | 0 | 225 |
| 5 | 2 | World wide | 15.00 | 0 | 0 | 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20... |
| 6 | 1 | World wide Mail | 5.00 | 0 | 0 | 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20... |
+--------+-----------+-----------------+----------------+---------+---------+-------------------------------------------------------+
送货费
+----------+--------+-----+-------+
| chargeID | bandID | qty | price |
+----------+--------+-----+-------+
| 1 | 2 | 0 | 5.00 |
| 2 | 3 | 0 | 0.00 |
| 3 | 4 | 0 | 0.00 |
| 4 | 4 | 1 | 1.00 |
| 5 | 4 | 5 | 3.00 |
| 6 | 1 | 0 | 5.95 |
| 7 | 1 | 10 | 10.95 |
| 8 | 2 | 10 | 14.00 |
| 9 | 5 | 0 | 0.00 |
| 10 | 5 | 3 | 5.00 |
| 11 | 5 | 6 | 10.00 |
| 12 | 5 | 9 | 15.00 |
| 13 | 6 | 0 | 0.00 |
| 14 | 6 | 2 | 5.00 |
| 15 | 6 | 4 | 10.00 |
| 16 | 6 | 6 | 15.00 |
+----------+--------+-----+-------+
当我尝试将费用表添加为子查询然后限制该查询时,它给了我所有费用表字段的 NULL
如果我尝试以下查询:
SELECT
`service`.`name`,
`charge`.`qty`,
`service`.`serviceID`,
`band`.`bandID`,
`band`.`initial_charge`,
`charge`.`chargeID`,
MAX( `charge`.`price` ) AS `price`,
`band`.`initial_charge` + `charge`.`price` AS `total_price`
FROM
`delivery_band` AS `band`
LEFT JOIN
`delivery_charge` AS `charge`
ON
`charge`.`bandID` = `band`.`bandID`
AND
`charge`.`qty` < '3'
LEFT JOIN
`delivery_service` AS `service`
ON
`service`.`serviceID` = `band`.`serviceID`
WHERE
FIND_IN_SET( '225', `band`.`accepted_countries` )
AND
(
`band`.`min_qty` >= '3'
OR
`band`.`min_qty` = '0'
)
AND
(
`band`.`max_qty` <= '3'
OR
`band`.`max_qty` = '0'
)
GROUP BY
`service`.`serviceID`
我得到这个返回:
+------------------+-----+-----------+--------+----------------+----------+-------+-------------+
| name | qty | serviceID | bandID | initial_charge | chargeID | price | total_price |
+------------------+-----+-----------+--------+----------------+----------+-------+-------------+
| Royal mail | 0 | 1 | 4 | 2.00 | 3 | 1.00 | 2.00 |
| APC | 0 | 2 | 1 | 0.00 | 6 | 5.95 | 5.95 |
| Collect in store | 0 | 3 | 3 | 0.00 | 2 | 0.00 | 0.00 |
+------------------+-----+-----------+--------+----------------+----------+-------+-------------+
原则上看起来不错,直到您意识到chargeID = 3 的价格为 0.00,但表格显示的价格为 1.00,因此这些值似乎已解除关联