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TA贡献1853条经验 获得超6个赞
只需加入三次即可。你已经做过一次了。例如:
SELECT
r.service,
r.amount,
pp.payment as prepayment,
pp.status as prepayment_status,
lp.payment as last_payment,
lp.status as last_payment_status,
ct.payment as cost_of_tolls,
ct.status as cost_of_tolls_status
FROM mzmx_request r
left JOIN mzmx_payment pp ON r.prepayment = pp.id
left JOIN mzmx_payment lp ON r.lastpayment = lp.id
left JOIN mzmx_payment ct ON r.costoftolls = ct.id
由于您要针对同一张表加入三次,因此您需要为该表添加别名。在这种情况下,我使用别名pp、lp和ct分别表示预付款、最后付款和通行费。
TA贡献1735条经验 获得超5个赞
3 个引用字段是独立的 - 因此它们需要独立的引用表副本:
SELECT *
FROM main
JOIN slave AS slave1 ON main.prepayment = slave1.id
JOIN slave AS slave2 ON main.last_payment = slave2.id
JOIN slave AS slave3 ON main.cost_of_tolls = slave3.id
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