使用MySQL从不同表中查询列表项（含表结构示例）

Got it, let's walk through how to query data from your two tables. First, let's restate your table structures clearly for reference:

Inventory Table #

SalesTaxes Table #

Now let's cover common query scenarios you might need:

1. Fetch all inventory items #

If you just need to pull every entry from the Inventory table with all its details, use this straightforward SELECT statement:

SELECT INV_Id, INV_Name, INV_Rate
FROM Inventory;

This will return all rows exactly as they appear in your Inventory table structure.

2. Fetch all sales tax entries #

Similarly, to get every tax record from the SalesTaxes table:

SELECT STX_Id, STX_TaxeName, STX_Amount
FROM SalesTaxes;

3. Combine data from both tables (assuming a relationship) #

If your inventory items link to specific taxes (even though you didn't include a foreign key in the given structure), let's say there's an INV_STX_Id column in Inventory that maps to STX_Id in SalesTaxes. You can join the tables to get combined data like this:

SELECT 
    i.INV_Id,
    i.INV_Name,
    i.INV_Rate,
    s.STX_TaxeName,
    s.STX_Amount
FROM Inventory i
JOIN SalesTaxes s ON i.INV_STX_Id = s.STX_Id;

If you want to include inventory items that don't have an associated tax (and show NULL for tax fields), swap JOIN with LEFT JOIN.

4. Filter specific items #

For example, to get only inventory items with a rate higher than 18:

SELECT INV_Name, INV_Rate
FROM Inventory
WHERE INV_Rate > 18.00;

Or to get taxes with an amount greater than 5:

SELECT STX_TaxeName, STX_Amount
FROM SalesTaxes
WHERE STX_Amount > 5.000;

If you had a specific combined query in mind—like calculating total cost including tax for inventory items—just let me know and I can tweak this further!

内容的提问来源于stack exchange，提问作者user9516731