--- title: 'PostgreSQL OR Operator' page_title: 'PostgreSQL OR Operator' page_description: 'In this tutorial, you will learn about the PostgreSQL OR logical operator and how to use it to combine multiple boolean expressions.' prev_url: 'https://www.postgresqltutorial.com/postgresql-tutorial/postgresql-or/' ogImage: '/postgresqltutorial/film.png' updatedOn: '2024-02-12T11:31:51+00:00' enableTableOfContents: true previousLink: title: 'PostgreSQL AND Operator' slug: 'postgresql-tutorial/postgresql-and' nextLink: title: 'PostgreSQL LIMIT' slug: 'postgresql-tutorial/postgresql-limit' --- **Summary**: in this tutorial, you will learn about the PostgreSQL `OR` logical operator and how to use it to combine multiple boolean expressions. ## Introduction to the PostgreSQL OR operator In PostgreSQL, a [boolean](postgresql-boolean) value can have one of three values: `true`, `false`, and `null`. PostgreSQL uses `true`, `'t'`, `'true'`, `'y'`, `'yes'`, `'1'` to represent `true` and `false`, `'f'`, `'false'`, `'n'`, `'no'`, and `'0'` to represent `false`. A boolean expression is an expression that evaluates to a boolean value. For example, the expression `1<>1` is a boolean expression that evaluates to `false`: ```phpsqlsql SELECT 1 <> 1 AS result; ``` Output: ```text result -------- f (1 row) ``` The letter `f` in the output indicates `false`. The `OR` operator is a logical operator that combines multiple boolean expressions. Here’s the basic syntax of the `OR` operator: ```sql expression1 OR expression2 ``` In this syntax, `expression1` and `expression2` are boolean expressions that evaluate to `true`, `false`, or `null`. The `OR` operator returns `true` only if any of the expressions is `true`. It returns `false` if both expressions are false. Otherwise, it returns null. The following table shows the results of the `OR` operator when combining `true`, `false`, and `null`. | OR | True | False | Null | | --------- | ---- | ----- | ---- | | **True** | True | True | True | | **False** | True | False | Null | | **Null** | True | Null | Null | In practice, you usually use the `OR` operator in a [`WHERE`](postgresql-where) clause to ensure that either of the specified expressions must be true for a row to be included in the result set. ## PostgreSQL OR operator Let’s explore some examples of using the `OR` operator. ### 1\) Basic PostgreSQL OR operator examples The following example uses the `OR` operator to combine `true` with `true`, which returns `true`: ```sql SELECT true OR true AS result; ``` Output: ```text result -------- t (1 row) ``` The following statement uses the `OR` operator to combine `true` with `false`, which returns true: ```sql SELECT true OR false AS result; ``` Output: ```text result -------- t (1 row) ``` The following example uses the `OR` operator to combine `true` with `null`, which returns `true`: ```sql SELECT true OR null AS result; ``` Output: ```text result -------- t (1 row) ``` The following example uses the `OR` operator to combine `false` with `false`, which returns `false`: ```sql SELECT false OR false AS result; ``` Output: ```text result -------- f (1 row) ``` The following example uses the `OR` operator to combine `false` with `null`, which returns `null`: ```sql SELECT false OR null AS result; ``` Output: ```text result -------- null (1 row) ``` The following example uses the `OR` operator to combine `null` with `null`, which returns `null`: ```sql SELECT null OR null AS result; ``` Output: ``` result -------- null (1 row) ``` ### 2\) Using the OR operator in the WHERE clause We’ll use the `film` table from the [sample database](../postgresql-getting-started/postgresql-sample-database) for the demonstration: ![](/postgresqltutorial/film.png)The following example uses the `OR` operator in the `WHERE` clause to find the films that have a rental rate is `0.99` or `2.99`: ``` SELECT title, rental_rate FROM film WHERE rental_rate = 0.99 OR rental_rate = 2.99; ``` Output: ```text title | rental_rate -----------------------------+------------- Academy Dinosaur | 0.99 Adaptation Holes | 2.99 Affair Prejudice | 2.99 African Egg | 2.99 ... ``` ## Summary - Use the `OR` operator to combine multiple boolean expressions.