What are the differences between AND and OR operators in SQL?

What are the differences between AND and OR operators in SQL?

In SQL, the AND operator is used to combine multiple conditions, and all conditions must be true for a record to be selected. The OR operator, on the other hand, allows for any of the conditions to be true for a record to be selected.

Can you give me an example of how to use both operators in a query?

Sure! For example, if you have a table called 'Employees', you could use: SELECT * FROM Employees WHERE Department = 'Sales' AND Salary > 50000; This will return employees in the Sales department with a salary greater than 50,000. Using OR, you could write: SELECT * FROM Employees WHERE Department = 'Sales' OR Department = 'Marketing'; This will return employees from either department.

What happens if I mix AND and OR in the same query?

When mixing AND and OR, it's important to use parentheses to group conditions. For example: SELECT * FROM Employees WHERE (Department = 'Sales' OR Department = 'Marketing') AND Salary > 50000; This ensures that the OR condition is evaluated first.

Are there any performance considerations when using these operators?

Yes, using AND and OR can affect query performance. Generally, AND conditions can be more efficient because they reduce the result set more quickly. However, the actual performance can depend on the database structure and indexing.