What are Inner Joins?
Inner Joins are the most commonly used type of Joins are are almost the same thing that you just learnt above. Check the following query SELECT * FROM (authors INNER JOIN books ON authors.author_id = books.author_id) This would return 4 rows of data having all the information about the 4 books. This gives exactly the same result as the following query SELECT * FROM authors,books WHERE authors.author_id = books.author_id Basically Inner Joins combines all the records in the first table with all the records in the second table and then selects those rows depending on the criteria that is present after the the ON keyword in the query. The most important thing to remember in Inner Joins is that only those records from both the tables are combined where there is a corresponding value in both the tables. You will understand this point clearly when you read about Outer Joins.
