MySQL Length function is one of the String methods, which is useful to find the length of the user-specified expression (or column value). Or we can simply say, the MySQL String Length Function counts the number of characters inside an expression and returns the results and the basic syntax of it is as shown below:
SELECT LENGTH (String_Expression) FROM Source
For this String Length Function demonstration, we are going to use the below-shown data
MySQL String Length Example
The string length function counts the number of characters inside a specified expression. The following query shows multiple ways to use this.
SELECT LENGTH ('Learn MySQL Server') AS `SQLLength`, LENGTH ('Tutorial Gateway') AS `Website Length`;
Remember, it counts the empty space as well.
This method also allows you to find the length of the data inside the columns. In this MySQL example, we are going to find the length of two columns Department Name and Email column.
SELECT FirstName, LastName, DepartmentName, LENGTH(DepartmentName) AS 'Department Length', Email, LENGTH(Email) AS 'Email Length' FROM employe;
MySQL Length Function WHERE Condition
In this String method example, we show you, How to use this at the where clause condition. First, we are finding the length of the Department Name and the Email columns. Next, we used it in the where clause to check whether the email characters are greater than 15 or not.
SELECT FirstName, LastName, DepartmentName, LENGTH(DepartmentName) AS 'Department Length', Email, LENGTH(Email) AS 'Email Length' FROM employe WHERE LENGTH(Email) > 15;
Instead of using this method in the where clause, you might be tempted to use the Alias name in the where clause. But, MySQL WHERE Clause does not understand the ALIAS Column name declared in the SELECT Statement.
String Length Command prompt Example
In this example, we write the string length function in Command prompt. Here, we are using this function along with the Where clause and Order By Clause. First, Where will restrict the records whose department name character count is greater than five. Next, Order by sorting the records in rever order based on their characters.
SELECT FirstName, LastName, DepartmentName, LENGTH(DepartmentName) AS `Department Length`, Email, LENGTH(Email) AS `Email Length` FROM employe WHERE LENGTH(DepartmentName) > 5 ORDER BY `Department Length` DESC;