有關mysql兩張表合併語法請教

mysql sql 合併資料表 mssql

coolmaster2160 2019-07-04 23:12:47 ‧ 6124 瀏覽

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想請教大家一下我有兩張透過select產生的表，分別如下
表1:
SELECT processors.device_id,ROUND(AVG(processor_usage),2) FROM processors GROUP BY processors.device_id

表2:
select
devices.device_id,devices.hostname,devices.sysName,mempools.mempool_descr,mempools.mempool_perc,storage.storage_descr,storage.storage_perc
from devices INNER JOIN mempools ON devices.device_id=mempools.device_id INNER JOIN storage ON devices.device_id=storage.device_id
WHERE (mempools.mempool_descr='Physical memory' OR mempools.mempool_descr='Real Memory') AND (storage.storage_descr = '/' OR storage.storage_descr = 'C:')

想問一下要怎麼下SQL語法才能產生類似下面這張透過device_id合併過後表，試了很久都不行，請前輩幫幫忙感謝!!

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2 個回答

rogeryao

iT邦超人 7 級 ‧ 2019-07-05 00:07:04

SELECT * FROM (表1 SQL) AS TableA
LEFT JOIN (表2 SQL) AS TableB ON TableB.device_id=TableA.device_id

LEFT JOIN 或 INNER JOIN

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coolmaster2160 iT邦新手 5 級 ‧ 2019-07-10 11:02:13 檢舉

真的成功了謝謝~!

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tine0961

iT邦新手 5 級 ‧ 2019-07-10 08:18:37

大概寫法如下

select
devices.device_id,devices.hostname,devices.sysName,mempools.mempool_descr,mempools.mempool_perc,storage.storage_descr,storage.storage_perc,ROUND(AVG(processor_usage),2)
from devices
INNER JOIN mempools ON devices.device_id=mempools.device_id
INNER JOIN storage ON devices.device_id=storage.device_id
join processors on devices.device_id==processors.device_id
WHERE (mempools.mempool_descr='Physical memory' OR
mempools.mempool_descr='Real Memory') AND (storage.storage_descr = '/' OR storage.storage_descr = 'C:')
group by devices.device_id,devices.hostname,devices.sysName,mempools.mempool_descr,mempools.mempool_perc,storage.storage_descr,storage.storage_perc