在sql

Question

我有3张桌子。

1. 股票
   • stock_id (PK)
   • barang_id(FK)
2. Stock_invoice
   • stock_invoice_id(PK)
   • stock_id(FK)
   • invoice_id(FK)
3. 啷
   • barang_id(PK)
   • stock_id(FK)
   • name_barang

我想显示尚未输入stock_invoice表的库存数据。然后我按如下方式编写查询

SELECT a.stock_id,a.barang_id, b.stock_invoice_id FROM stock a LEFT JOIN stock_invoice b ON a.stock_id=b.stock_id WHERE b.stock_id IS NULL

但我有问题如何选择Barang表的name_barang

Answer 1

你需要加入第三个表

SELECT a.stock_id,c.name_barang, b.stock_invoice_id
FROM stock a
LEFT JOIN stock_invoice b ON a.stock_id=b.stock_id
JOIN barang c ON a.barang_id = c.barang_id 
WHERE b.stock_id IS NULL

Answer 2

试试这个： -

SELECT a.stock_id,a.barang_id,c.name_barang,b.stock_invoice_id
FROM stock a
LEFT JOIN stock_invoice b ON a.stock_id=b.stock_id
LEFT JOIN Barang c  ON a.barang_id=c.barang_id 
WHERE b.stock_id IS NULL

Answer 3

你需要一个三向连接，

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