Not easy to guess the intention of the query, but to me the query would make more sense as:

SELECT t_product.productid
    ,  t_order.orderid
    ,  t_orderItem.itemid
FROM t_order  
JOIN t_orderItem 
    ON t_order.orderid=t_orderItem.orderid
JOIN t_product      
    ON t_product.productid = t_orderItem.productid  
WHERE t_order.customerid = 101 

If we look at the query mentioned in the comment on the question:

FROM t_product
JOIN t_order 
    ON t_order.customerid = 101 
JOIN t_orderItem 
    ON t_product.productid = t_orderItem.productid 
WHERE t_order.orderid=t_orderItem.orderid

Since we are now dealing only with INNER JOINs we can logically move predicates between the JOIN clause and the WHERE clause. We can also change the order of the JOINs. I would think of this as:

• An ORDER has ORDERITEMS

    FROM t_order  
    JOIN t_orderItem 
        ON t_order.orderid=t_orderItem.orderid
  

• An ORDERITEM references a PRODUCT

         t_orderItem 
    JOIN t_product      
        ON t_product.productid = t_orderItem.productid
  

• A CUSTOMER orders an ORDER

         WHERE t_order.customerid = 101 
  

Gluing this together would be:

SELECT t_product.productid
    ,  t_order.orderid
    ,  t_orderItem.itemid
FROM t_order  
JOIN t_orderItem 
    ON t_order.orderid=t_orderItem.orderid
JOIN t_product      
    ON t_product.productid = t_orderItem.productid  
WHERE t_order.customerid = 101 

If you want to have ORDERs that not yet have any ORDERITEMS you could use a LEFT JOIN between ORDER and ORDERITEMS (I don't think it will be any use in having an ORDERITEM without a PRODUCT)

SELECT t_product.productid
    ,  t_order.orderid
    ,  t_orderItem.itemid
FROM t_order  
LEFT JOIN t_orderItem 
    ON t_order.orderid=t_orderItem.orderid
JOIN t_product      
    ON t_product.productid = t_orderItem.productid  
WHERE t_order.customerid = 101 

I would say that the intent of these queries is easier to understand than the query we started with.