LENGTH and CHAR_LENGTH in SQL

Introduction

These functions help you find out how many characters or bytes are in a text. This is useful when you want to check the size of words or sentences stored in your database.

When you want to count how many characters are in a username to enforce length rules.

When you need to find the size of a text message before sending it.

When checking if a product description is too long for display.

When comparing the length of two different text fields.

When validating input length in a database query.

Syntax

SQL

LENGTH(string)
CHAR_LENGTH(string)

LENGTH counts the number of bytes used by the string, which can be different from the number of characters if the string contains multi-byte characters.

CHAR_LENGTH counts the number of characters, regardless of how many bytes each character uses.

Examples

Returns 5 because 'hello' has 5 characters and each is one byte.

SQL

SELECT LENGTH('hello');

Also returns 5 because there are 5 characters.

SQL

SELECT CHAR_LENGTH('hello');

Returns 5 because the 'é' character uses 2 bytes in UTF-8 encoding.

SQL

SELECT LENGTH('café');

Returns 4 because there are 4 characters.

SQL

SELECT CHAR_LENGTH('café');

Sample Program

This query shows the difference between LENGTH and CHAR_LENGTH for the word 'database'.

SQL

SELECT LENGTH('database') AS length_bytes, CHAR_LENGTH('database') AS length_chars;

Important Notes

If your text contains only simple ASCII characters, LENGTH and CHAR_LENGTH will return the same number.

For languages with special characters (like accented letters or emojis), LENGTH may return a larger number than CHAR_LENGTH.

Use CHAR_LENGTH when you want to count characters as people see them, not bytes.

Summary

LENGTH counts bytes, CHAR_LENGTH counts characters.

They help check text size in databases.

Use CHAR_LENGTH for user-friendly character counts.