在SQL中的聯接查詢中選擇另一個表

Question

我有3張桌子。

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

我想顯示尚未輸入到stock_invoice表中的庫存數據。 然后我寫查詢如下

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

但我有問題如何選擇name_barang表的name_barang

Answer 1

你需要加入第三張桌子

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

嘗試這個 ：-

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

您需要三種方式的加入，

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