LENGTH() Function in SQL

Last Updated : 7 Sep, 2026

The LENGTH() function in SQL is a string function used to return the length of a string. Depending on the database system, it may return the number of characters or bytes in the given string.

  • Used to determine the length of string values.
  • Useful for validating and analyzing text data stored in database tables.
  • Behavior of LENGTH() can differ across SQL database systems.

Syntax

LENGTH(Input_String)
  • Input_String: The string or column whose length you want to find.

Examples

Now let us see some examples of the LENGTH() function to understand its working better.

Example 1: Find the Length of a String

In this example, we will find the length of a simple string.

Query:

SELECT LENGTH('Hello World') AS string_length;

Output:

Screenshot-2026-09-02-123030
  • Counts the characters/bytes present in the string according to the database system.
  • The space between Hello and World is also included.

Example 2: Use LENGTH() with a Table Column

Let us create a table containing the names of users.

Screenshot-2026-09-02-123133

Now, we can use the LENGTH() function to find the length of each name.

Query:

SELECT name,
       LENGTH(name) AS name_length
FROM users;

Output:

Screenshot-2026-09-02-123447
  • Returns the length of each value in the name column.
  • The result is displayed as name_length.

Example 3: LENGTH() with Empty String

The LENGTH() function can also be used with an empty string.

Query:

SELECT LENGTH('') AS string_length;

Output:

Screenshot-2026-09-02-123052
  • An empty string contains no characters or bytes.
  • Therefore, LENGTH('') returns 0.

Note: LENGTH() is supported by databases such as MySQL, PostgreSQL and Oracle. In MySQL, LENGTH() returns the number of bytes, while CHAR_LENGTH() returns the number of characters. SQL Server uses LEN() instead of LENGTH().

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