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我一直在努力实现的目标是根据3个不同变量拉动价格:brand_id
,model_id
,motor_id
。使用3个不同变量获取INNER JOIN的价格
的表,我有工作设计:
唯一的问题是,当我添加一个INNER JOIN为databaseapp_lkp_prices
我得到一个零结果集(仅供参考,没有任何价格目前设定databaseapp_lkp_prices
是一个空表)
我期待看到NULL
到位price
为48,000记录存在的时候,不添加databaseapp_lkp_prices
INNER JOIN
我的查询是:
SELECT
a.brand,
b.model,
c.motor,
d.ecu_hardware_ver,
d.ecu_software_ver,
d.ecu_software_upg_ver,
d.ecu_brand,
d.ecu_type,
d.eprom,
d.eprom_desc,
d.`checksum`,
d.checksum16,
c.motor_hp * 1.2 AS motor_hp,
e.price,
c.motor_id,
c.model_id,
c.brand_id
FROM
databaseapp_brand AS a
INNER JOIN databaseapp_model AS b ON b.brand_id = a.brand_id
INNER JOIN databaseapp_motor AS c ON b.model_id = c.model_id
INNER JOIN databaseapp_ecu AS d ON d.motor_id = c.motor_id
INNER JOIN databaseapp_lkp_prices AS e ON c.brand_id = e.brand_id AND c.model_id = e.model_id AND c.motor_id = e.motor_id
ORDER BY
a.brand ASC,
b.model ASC
任何人能帮助我,为什么我得到一个零结果集,当我尝试查找的价格。
干杯!
内部连接需要匹配。不匹配不行。您应该尝试使用LEFT JOIN而不是INNER JOIN for databaseapp_lkp_prices贡献。 –
完美的,谢谢 - 发布作为答案,我会接受。 – zanderwar
你好。 –