Introduction to the LIKE Statement in SQL

Introduction

The LIKE statement in SQL is one of the important tools for searching within database entries. This statement allows you to filter data in a more flexible and complex manner than simple conditional expressions, enabling you to find data that meets your criteria. The LIKE tool actually searches strings using specific characters like % and _. In this article, we will examine and use this statement.

Using LIKE

In cases where you want to find records in textual fields that match a specific pattern, the LIKE statement is widely used. For instance, let's suppose we want to find all usernames that start with a specific letter or have a specific character in the text field, we can use LIKE. This is one of the main uses of LIKE.

Special Characters

In the LIKE statement, there are two special characters that can help you in your search: % and _. The character % represents zero or more characters, while the character _ represents a single character. In this way, you can fine-tune your search patterns in various ways.

Examples of Using LIKE

Now, here's a code example that shows how to use LIKE in SQL queries.

  SELECT * FROM users WHERE username LIKE 'a%';
  SELECT * FROM users WHERE username LIKE '_b%';
  SELECT * FROM users WHERE username LIKE '%xyz%';
  

Explanation of Code

SELECT * FROM users WHERE username LIKE 'a%';
This line selects all users whose usernames begin with the letter 'a'.

SELECT * FROM users WHERE username LIKE '_b%';
This line selects all users whose second character in the username is 'b'.

SELECT * FROM users WHERE username LIKE '%xyz%';
This line selects all users whose usernames contain the substring 'xyz'.