在WHERE子句中加入第3个表

Question

I'm trying to extend a 2 table join query to join 3 tables. I'm using PDO

SELECT tb.product, COUNT(tb.ID) AS nums FROM items tb LEFT JOIN itemCode cod ON tb.ID = cod.codeID WHERE tb.product = :product AND cod.name = :cName

The above 2 table join works. My question is, how do I match itemCode's availabilityID column to tblC's stockID column and add it to the WHERE clause with same query to get the result?

So basically I want to check if the availabilityID column of itemCode table match with stockID column of tblC table.

EDIT: table structure:

**items table**
ID   |  product 

**itemCode table** 
codeID   |  name 

**tblC table**
stockID

Answer 1

As stated in your question you want to match availabilityID with stockID, this is what the query does. However, the availabilityID does not show up in your edit.

SELECT tb.product, COUNT(tb.ID) AS nums
FROM items tb
LEFT JOIN itemCode cod ON tb.ID = cod.codeID
JOIN tblC stock ON stock.`stockID` = cod.`availabilityID`
WHERE tb.product = :product AND cod.name = :cName