PostgreSQL LENGTH() function

LENGTH() function

The PostgreSQL length() function is used to determine the number of characters in a given string. It is useful for evaluating string lengths in various contexts, such as data validation, formatting, and analysis.

Uses of LENGTH() Function

• Determine String Length: Calculate the number of characters in a string.


• Data Validation: Ensure that strings meet certain length requirements.


• Filtering Data: Use in WHERE clauses to filter results based on string length.


• Data Formatting: Format output based on string length for better readability.


• Performance Optimization: Optimize queries and data storage by analyzing string lengths.


• Combining with Other Functions: Use alongside other string functions for complex data manipulations.

Syntax:

length(<string>)

PostgreSQL Version: 9.3

Pictorial Presentation of PostgreSQL LENGTH() function

Example: PostgreSQL LENGTH() function:

In the example below the length function returns the length of the given string 'w3resource'.

Code:

SELECT length('w3resource')
AS "Length of a String";

Sample Output:

 Length of a String
--------------------
                 10
(1 row)

Example of PostgreSQL LENGTH() function using column :

Sample Table: employees

The example below, returns the first_name and the length of first_name ( how many characters contain in the first name ) from the employees where the length of first_name is more than 7.

Code:

SELECT first_name,length(first_name) 
AS "Length of a First Name" 
FROM employees 
WHERE length(first_name)>7;

Sample Output:

 first_name  | Length of a First Name
-------------+------------------------
 Alexander   |                      9
 Jose Manuel |                     11
 Alexander   |                      9
 Christopher |                     11
 Danielle    |                      8
 Harrison    |                      8
 Elizabeth   |                      9
 Jonathon    |                      8
 Kimberely   |                      9
 Jennifer    |                      8
 Jennifer    |                      8
(11 rows)

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