我很抱歉我的英語(yǔ)不好。我有一個(gè)項(xiàng)目注冊(cè)表：比如Type of service | Total Amount | prepayment | last payment | Cost of tolls web design | 1000 | 1 (F-key) | 2 (F-key) | 3 (F-key)付款狀態(tài)和金額的第二個(gè)表 id | amount | Payment status | Description 1 | 400 | yes | for prepayment 2 | 600 | no | for last payment 3 | 0 | no | for Cost of tolls 現(xiàn)在我的問題是：如何連接兩個(gè)表并取出所有三列？我已經(jīng)用這段代碼取出了預(yù)付款欄SELECT mzmx_request.service, mzmx_request.amount,(mzmx_payment.payment) as prepayment,(mzmx_payment.status) as prepayment_status FROM mzmx_requestJOIN mzmx_payment ON mzmx_request.prepayment = mzmx_payment.id如何再添加兩列？JOIN mzmx_payment ON mzmx_request.payment = mzmx_payment.idJOIN mzmx_payment ON mzmx_request.pay_more = mzmx_payment.id
2 回答
墨色風(fēng)雨
TA貢獻(xiàn)1853條經(jīng)驗(yàn) 獲得超6個(gè)贊
只需加入三次即可。你已經(jīng)做過一次了。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
由于您要針對(duì)同一張表加入三次，因此您需要為該表添加別名。在這種情況下，我使用別名pp、lp和ct分別表示預(yù)付款、最后付款和通行費(fèi)。
喵喔喔
TA貢獻(xiàn)1735條經(jīng)驗(yàn) 獲得超5個(gè)贊
3 個(gè)引用字段是獨(dú)立的 - 因此它們需要獨(dú)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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