PostgreSQL - IS NULL operator Last Updated : 01 Aug, 2024 Summarize Comments Improve Suggest changes Share Like Article Like Report The PostgreSQL IS NULL operator is used to check whether a value is NULL. In the context of databases, NULL indicates that data is either missing or not applicable. Since NULL cannot be compared directly with any integer or string (as such comparisons result in NULL, meaning an unknown result), the IS NULL operator is crucial for identifying NULL values.SyntaxValue IS NULL;PostgreSQL IS NULL operator ExamplesFor the sake of this article, we will be using the sample DVD rental database, which is explained here and can be downloaded by clicking on this link in our examples.Let us take a look at some of the examples of the IS NULL operator in PostgreSQL to better understand the concept.Example 1: Find Customers Without Email AddressesHere we will make a query to find all the 'first_name' and 'last_name' of customers that don't have an "email" in the "customer" table of our sample database. Query:SELECT first_name, last_name FROM customer WHERE email IS NULL;Output:Explanation: This query selects the 'first_name' and 'last_name' of customers whose email field is NULL. This is useful for identifying customers who haven't provided an email address.Example 2: Find Films Without Release YearHere we will make a query to find all the "title" of the films that don't have a "release_year" in the "film" table of our sample database. Query:SELECT title FROM film WHERE release_year IS NULL;Output:Explanation: This query retrieves the titles of films where the 'release_year' is NULL. This can help identify films that are missing release year information.Important Points PostgreSQL IS NULL operatorThe IS NULL operator is used to check whether a value in a column is NULL.Avoid using equality operators (= or !=) with NULL. Always use IS NULL or IS NOT NULL.Indexes on columns containing 'NULL' values can affect query performance. Proper indexing strategies are crucial.In the context of databases, NULL represents missing, undefined, or not applicable data. It is different from an empty string or zero. Comment More infoAdvertise with us Next Article PostgreSQL - NOT LIKE operator R RajuKumar19 Follow Improve Article Tags : PostgreSQL postgreSQL-operators Similar Reads PostgreSQL - ANY Operator The ANY operator in PostgreSQL is a powerful tool for comparing a scalar value against a set of values returned by a subquery. From this article, we can better understand the ANY Operator in PostgreSQL.Syntaxexpression operator ANY(subquery)Rules of ANY Operator The below rules must be followed whil 3 min read PostgreSQL - NOT LIKE operator The PostgreSQL NOT LIKE operator is a powerful tool used in SQL queries to filter out rows that do not match specific patterns. By utilizing this operator, users can eliminate undesired string patterns from their results, enabling more precise data retrieval. It is particularly beneficial in scenari 3 min read PostgreSQL - EXISTS Operator The EXISTS operator in PostgreSQL is a powerful SQL feature used to check the existence of rows in a subquery. It is particularly useful when working with correlated subqueries, where the inner query depends on values from the outer query. The EXISTS operator returns true if the subquery returns at 4 min read PostgreSQL - Assert PostgreSQL provides the ASSERT statement as a vital tool for inserting debugging checks in PL/pgSQL code. This statement is crucial for identifying logical errors, making it easier to catch problems in your code early on.Let us better understand the Assert Statement in PostgreSQL from this article.S 3 min read PostgreSQL - NULLIF() Function Effectively handling NULL values is important in database management, especially for ensuring data integrity and avoiding errors. PostgreSQL offers several powerful functions, such as NULLIF and COALESCE, to help manage NULL and empty values efficiently. In this article, we will guide us through the 4 min read NOT IN vs NOT EXISTS in PostgreSQL PostgreSQL is one of the most advanced general-purpose object-relational database management systems and is open-source. Being an open-source software, its source code is available under the PostgreSQL license, a liberal open-source license. Anyone with the right skills can use, modify, and distribu 4 min read Like