The LEFT JOIN: Matching records ... While there are other types of JOINs supported by various flavors of SQL, most implementations of SQL support the INNER JOIN, LEFT JOIN, and RIGHT JOIN constructs.

The left join updates all rows in table A. Inner join only updates rows in table A where there is a matching ID in table B. You're working with different row sets. Now if you said something like: ...

SELECT CustomerID, OrderID FROM Customers LEFT OUTER JOIN Orders ... Here is the SQL to compare the inner and outer JOINs: SELECT InnerOuter.T1.T1ID, InnerOuter.T1.NameAS Name1, ...