SQL Basics
Querying Data
Filtering Data
Joining Tables
SQL Functions
Modifying Data
Defining Data
SQL AND, OR, NOT
In this tutorial, you will learn how to combine multiple conditions in the WHERE clause using the logical operators AND and OR.
In the previous tutorial, you learned how to filter your data using one condition, but sometimes you need to filter rows based on multiple conditions. The logical operators allow you to use multiple comparisons in one query.
| AND | Return True if both conditions are True |
| OR | Return True if one of conditions is True |
| NOT | Reverse the result of any Boolean operator |
| IN | Return True if a value is in a set of values |
| BETWEEN | Return True if a value falls within a specific range |
| LIKE | Return True if a value matches a pattern |
These logical conditions always return true or false.
The  AND operator combines two conditions and returns TRUE only if both conditions are met and if one of the criteria is not met then it returns FALSE.
Syntax
The basic syntax of the AND clause to filter the data returned by a query can be given with:
SELECT
column_names
FROM table_name
WHERE condition1 AND condition2
The basic syntax of the OR clause to filter the data returned by a query can be given with:
SELECT column_names
FROM table_name
WHERE condition1 OR condition2
The basic syntax of the NOT clause to filter the data returned by a query can be given with:
SELECT column_names
FROM table_name
WHERE NOT condition
AND Example
To understand the ORDER BY statement in a better way, let’s look at the following customers table in our tutorial database:
| customer_id | first_name | last_name | country | score |
|---|---|---|---|---|
| 1 | Maria | Cramer | Germany | 350 |
| 2 | John | Steel | USA | 900 |
| 3 | Georg | Pipps | UK | 750 |
| 4 | Martin | Müller | Germany | 500 |
| 5 | Peter | Franken | USA | NULL |
Now, let’s check out some examples that demonstrate how it actually works.
We have the following task be to solve using SQL statements
The following SQL statement will returns all customers from customers table and order the result by the score column in ascending order.
You can have the same the result set by skipping the ASC, because it is the default option in ORDER BY.
SELECT *
FROM customers
WHERE country = 'Germany'
AND score < 400
After executing the above query, you’ll get the result set something like this:
Similarly, you can use the DESC option to perform a sorting in descending order. The following statement will orders the result set by the numeric salary column in descending order.
OR Example
As you can see the output contains everything the whole customers tables including all rows and columns.
SELECT *
FROM customers
WHERE country = 'Germany'
OR score < 400
NOT Example
You can filter your results in a number of ways using comparison and logical operators, which you’ll learn about in the next tutorials. I summarized in the following table the most important ones.
You can filter your results in a number of ways using comparison and logical operators, which you’ll learn about in the next tutorials. I summarized in the following table the most important ones.
SELECT *
FROM customers
WHERE NOT score < 400
