Introduction to the PostgreSQL LENGTH() function

The PostgreSQLLENGTH() function returns the number of characters in a string.

Here’s the basic syntax for theLENGTH() function:

LENGTH(string);

TheLENGTH() function accepts a string as a parameter. It can be any of the followingdata types:

• character or char
• character varying or varchar
• text

TheLENGTH() function returns an integer that represents the number of characters in the string. It returns NULL if the string is null.

PostgreSQL provides theCHAR_LENGTH() andCHARACTER_LENGTH() functions that provide the same functionality as theLENGTH() function.

PostgreSQL LENGTH() function examples

Let’s explore some examples of using theLENGTH() function.

1) Basic PostgreSQL LENGTH() function examples

The following example uses theLENGTH() function to get the length of a string:

SELECT  LENGTH ('PostgreSQL Tutorial');

Output:

length--------     19(1 row)

If you pass NULL to theLENGTH() function, it returns NULL.

SELECT  LENGTH (NULL);

Output:

length--------   null(1 row)

2) Using the PostgreSQL LENGTH() function with table data example

We’ll use thecustomer table from thesample database:

The following example uses theLENGTH() function to retrieve the first names and the number of characters of first names from thecustomer table:

SELECT  first_name,  LENGTH (first_name) lenFROM  customerORDER BY  len;

Output:

first_name  | len-------------+----- Jo          |   2 Sam         |   3 Roy         |   3 Eva         |   3 Don         |   3 Dan         |   3...

Summary

• Use the PostgreSQLLENGTH() function to get the number of characters of a string.

Last updated onJanuary 27, 2024

On this page

• Introduction to the PostgreSQL LENGTH() function
• PostgreSQL LENGTH() function examples
• Summary