![]() If pattern does not contain percent signs or underscores, then the pattern only represents the string itself in that case LIKE acts like the equals operator. An equivalent expression is NOT ( string LIKE pattern).) (As expected, the NOT LIKE expression returns false if LIKE returns true, and vice versa. The LIKE expression returns true if the string matches the supplied pattern. This write-up explained how to use the LIKE, NOT LIKE, and ILIKE operators in Postgres to perform Pattern matching.9.7.1. The LIKE operator is case sensitive while the ILIKE operator matches the search expression with the given pattern irrespective of the letter case. The NOT LIKE operator negates the results of the LIKE operator, which means the NOT LIKE operator will retrieve false if the match is found and true if the match is found in the string. The LIKE operator matches the search expression with the specified pattern and retrieves true if the match is found. ![]() The output shows that the NOT LIKE operator retrieves all the strings other than those that contain a substring “Function”. WHERE article_title NOT LIKE '%Function%' In this example, we will use the NOT LIKE operator instead of the LIKE operator to find all those strings that don’t have the “Function” substring in the article_title column: SELECT article_title Use the below-specified syntax to perform text matching using the NOT LIKE operator: SELECT FROM tab_nameĮxample: How Does the NOT LIKE Operator Work? What is a NOT LIKE Operator and How Does it Work? The output snippet proves that the “ILIKE” operator retrieves the data irrespective of the letter case. Let’s implement the ILIKE operator on the same previous example and see how it works: SELECT article_title Use the below-specified syntax to perform text matching using the NOT LIKE operator: SELECT FROM tab_nameĮxample: How Does the ILIKE Operator Work? The ILIKE operator matches the search expression with the given pattern irrespective of the letter case. What is ILIKE Operator and How Does it Work in Postgres? The above snippet proves that the LIKE operator is case-sensitive. The output snippet proves that there are two titles in the “artile_info” table that contain a substring “Function”.Įxample 2: Case-Sensitivity in LIKE Operator The LIKE operator is case-sensitive, so it will retrieve false if the perfect match does not found: SELECT article_title We will utilize the percent wildcard with the LIKE operator to find a substring “function” from the article_title column: SELECT article_title We have created a table named “article_info”, whose data is shown in the following snippet: SELECT * FROM article_info ![]() Use the wildcards to specify a pattern of your choice in place of a pattern.Įxample 1: How Does the LIKE Operator Work? Use the below-specified syntax to perform text matching using the LIKE operator: SELECT FROM tab_name The LIKE operator is case sensitive, which means the LIKE operator will consider “ABC” and “abc” two different strings and hence retrieves false in such a case. ![]() What is a LIKE Operator and How Does it Work? This write-up will teach you the difference between LIKE, ILIKE, and NOT LIKE operators in PostgreSQL. The percentage wildcard "%" matches sequences of characters, while the underscore "_" matches a single character. Two types of wildcards are used in Postgres to specify a pattern: a percentage sign, “%,” and an underscore sign, “_”. In PostgreSQL, LIKE, NOT LIKE, and ILIKE operators are used along with the wildcards to perform the pattern matching. ![]()
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