在sql中加入查询选择另一个表格

Question

我有3个表格。

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

我想显示尚未进入stock_invoi库存数据ce表。然后我写的查询，如下所示

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，如何选择啷表name_barang

Answer 1

您需要加入第三个表

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

您需要三方加入，

SELECT 
     a.stock_id, 
     a.barang_id, 
     b.stock_invoice_id, 
     c.name_barang 
    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