SQL Server String LEN() Function

SQL Server LEN() Function

The SQL Server LEN() function is used to return the number of characters in a string. This function is useful for string manipulation tasks, such as determining the length of a string for validation or formatting purposes.

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Syntax

SELECT LEN(string);

The LEN() function takes a single argument:

• string: The string whose length is to be calculated.

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Example SQL Server LEN() Function Queries

Let's look at some examples of SQL Server LEN() function queries:

1. Basic LEN() Example

SELECT LEN('Hello World') AS length;

This query returns the number of characters in the string 'Hello World'. The result will be:

length
------
11

2. LEN() with a Column

SELECT first_name, LEN(first_name) AS length
FROM employees;

This query returns the length of the first_name column for each employee. The result will show the first_name and its length.

3. LEN() with a Variable

DECLARE @myString VARCHAR(50);
SET @myString = 'SQL Server';
SELECT LEN(@myString) AS length;

This query uses a variable to store a string and then calculates its length. The result will be:

length
------
10

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Full Example

Let's go through a complete example that includes creating a table, inserting data, and using the LEN() function.

Step 1: Creating a Table

This step involves creating a new table named example_table to store some sample data.

CREATE TABLE example_table (
    id INT PRIMARY KEY,
    description VARCHAR(50)
);

In this example, we create a table named example_table with columns for id and description.

Step 2: Inserting Data into the Table

This step involves inserting some sample data into the example_table.

INSERT INTO example_table (id, description) VALUES (1, 'Apple');
INSERT INTO example_table (id, description) VALUES (2, 'Banana');
INSERT INTO example_table (id, description) VALUES (3, 'Cherry');

Here, we insert data into the example_table.

Step 3: Using the LEN() Function

This step involves using the LEN() function to calculate the length of the description column.

SELECT id, description, LEN(description) AS length
FROM example_table;

This query retrieves the id, description, and the length of the description column for each row in the example_table. The result will be:

id  description  length
--- ------------ ------
1   Apple        5
2   Banana       6
3   Cherry       6

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Conclusion

The SQL Server LEN() function is a powerful tool for determining the number of characters in a string. Understanding how to use the LEN() function and its syntax is essential for effective string manipulation and data processing in SQL Server.