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Databases SQL Basics Finding the Data You Want Review & Practice with SQL Playgrounds

kevin nadjarian
kevin nadjarian
1,498 Points
Posted by kevin nadjarian
kevin nadjarian
1,498 Points

Select Multiple table VS INNER JOIN?

what the different from this example (selecting multiple table / same column) with a INNER JOIN?

2 Answers

Xayaseth Boudsady
Xayaseth Boudsady
21,951 Points

First one pull all records within those two tables, then filters by the WHEREclause.

Second one, joins on record that meet the requirements on the ON clause.

Efficiency...

I ran the query and got the same results.

SELECT * FROM loans, books
WHERE loans.book_id = books.id;

SELECT * FROM loans
JOIN books ON loans.book_id = books.id;
Stephanie Youstra
Stephanie Youstra
18,513 Points
Stephanie Youstra
Stephanie Youstra
18,513 Points

I'm guessing they're doing it this way bc they haven't taught JOIN yet -- my sense is that it was tucked in there as a teaser, "Here's what else you'll be able to do, once you learn a little more!"