More Joins

The joins we were doing in the previous notes can be done with the JOIN ON syntax as well.
A Reference for MySQL

SELECT Buyer, SKU_DATA.SKU, QuantityOnHand, QuantityOnOrder 
   FROM SKU_DATA  JOIN INVENTORY ON SKU_DATA.SKU = INVENTORY.SKU;

Multiple JOINS are permitted

 
SELECT RETAIL_ORDER.OrderNumber, StoreNumber, OrderYear, ORDER_ITEM.SKU,
       SKU_Description, Department 
   FROM RETAIL_ORDER JOIN ORDER_ITEM 
            ON RETAIL_ORDER.OrderNumber=ORDER_ITEM.OrderNumber 
	JOIN SKU_DATA 
	    ON ORDER_ITEM.SKU=SKU_DATA.SKU;

Sometimes we have NULL data, and we want the columns to show up anyway.
- He introduces a new example
- STUDENT(StudentPK,StudentName,LockerFK)
- LOCKER(LockerPK, LockerType)
- Student.sql in my 313/ch2 directory.
- Note, two students are not assigned lockers
- ```
SELECT *
    FROM STUDENT JOIN LOCKER
          ON STUDENT.LockerFK=LOCKER.LockerPK;
	
```
- Note, only the matches show up, but what if we want everything?
- ```
SELECT *
    FROM STUDENT LEFT JOIN LOCKER
          ON STUDENT.LockerFK=LOCKER.LockerPK;
	
```
- ```
SELECT *
    FROM STUDENT RIGHT JOIN LOCKER
          ON STUDENT.LockerFK=LOCKER.LockerPK;
	
```
- These are called outer joins