What are some best practices for writing SQL queries?

What are some best practices for writing SQL queries?

Some best practices include using meaningful table and column names, avoiding SELECT *, and using JOINs instead of subqueries when possible.

Why should I avoid using SELECT *?

Using SELECT * can lead to performance issues, as it retrieves all columns, even those you don't need, which increases data transfer.

What about indexing? How does it help?

Indexing improves query performance by allowing the database to find rows faster, but it should be used judiciously to avoid overhead.

Can you explain the difference between INNER JOIN and LEFT JOIN?

INNER JOIN returns only the rows with matching values in both tables, while LEFT JOIN returns all rows from the left table and matched rows from the right.