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
Visual Presentation of PostgreSQL LENGTH() function
Example: PostgreSQL LENGTH() function:
In the example below the length function returns the length of the given string 'w3resource'.
SQL Code:
SELECT length('w3resource')
AS "Length of a String";
Output:
Length of a String
--------------------
10
(1 row)
Example of PostgreSQL LENGTH() function using column :
Sample Table: employees.
employee_id | first_name | last_name | email | phone_number | hire_date | job_id | salary | commission_pct | manager_id | department_id
-------------+-------------+-------------+----------+--------------------+------------+------------+----------+----------------+------------+---------------
100 | Steven | King | SKING | 515.123.4567 | 1987-06-17 | AD_PRES | 24000.00 | 0.00 | 0 | 90
101 | Neena | Kochhar | NKOCHHAR | 515.123.4568 | 1987-06-18 | AD_VP | 17000.00 | 0.00 | 100 | 90
102 | Lex | De Haan | LDEHAAN | 515.123.4569 | 1987-06-19 | AD_VP | 17000.00 | 0.00 | 100 | 90
103 | Alexander | Hunold | AHUNOLD | 590.423.4567 | 1987-06-20 | IT_PROG | 9000.00 | 0.00 | 102 | 60
104 | Bruce | Ernst | BERNST | 590.423.4568 | 1987-06-21 | IT_PROG | 6000.00 | 0.00 | 103 | 60
105 | David | Austin | DAUSTIN | 590.423.4569 | 1987-06-22 | IT_PROG | 4800.00 | 0.00 | 103 | 60
106 | Valli | Pataballa | VPATABAL | 590.423.4560 | 1987-06-23 | IT_PROG | 4800.00 | 0.00 | 103 | 60
107 | Diana | Lorentz | DLORENTZ | 590.423.5567 | 1987-06-24 | IT_PROG | 4200.00 | 0.00 | 103 | 60
108 | Nancy | Greenberg | NGREENBE | 515.124.4569 | 1987-06-25 | FI_MGR | 12000.00 | 0.00 | 101 | 100
109 | Daniel | Faviet | DFAVIET | 515.124.4169 | 1987-06-26 | FI_ACCOUNT | 9000.00 | 0.00 | 108 | 100
..................
206 | William | Gietz | WGIETZ | 515.123.8181 | 1987-10-01 | AC_ACCOUNT | 8300.00 | 0.00 | 205 | 110
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.
SQL Code:
SELECT first_name,length(first_name)
AS "Length of a First Name"
FROM employees
WHERE length(first_name)>7;
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)
PREV : LEFT function
NEXT : LPAD function