Writing SQL queries can be complex and it's easy to make mistakes.
Here are some common mistakes to avoid when writing SQL queries
When writing queries with multiple tables, it's important to use table aliases to make the query more readable
If a query is running slowly, it's possible that the query is not using indexes properly.
Using the wrong join type can lead to incorrect results or slow query performance.
NULL values can cause unexpected results in queries if they are not handled properly.
Subqueries can be a powerful tool in SQL, but they can also slow down queries if they are not optimised properly.
It's important to test queries to ensure they are producing the expected results and running efficiently.
How to Use Subqueries in SQL: A Beginner’s Guide