PostgreSQL UPPER() function

UPPER() function

The PostgreSQL upper function is used to convert all characters in a given string to uppercase. This function is particularly useful for standardizing text data, ensuring consistent formatting for string comparisons, and preparing data for display purposes.

Uses of UPPER() Function

• Standardizing Text Data: Convert text to uppercase to ensure consistency across datasets.


• Improving Data Comparisons: Facilitate accurate string comparisons by converting both strings to uppercase.


• Data Cleaning: Uniformly format text data for easier manipulation and analysis.


• Preparing Data for Display: Ensure text is in uppercase for specific display requirements or conventions.


• Creating Uniform Identifiers: Standardize identifiers by converting them to uppercase.


• Formatting User Input: Convert user input to uppercase to match specific data format requirements.


• Query Optimization: Simplify queries by converting text fields to uppercase for consistent search results.

Syntax:

upper(string)

PostgreSQL Version: 9.3

Visual Presentation of PostgreSQL UPPER() function

Example: PostgreSQL UPPER() function:

In the following example PostgreSQL upper function returns lower case to uppercase.

SQL Code:

SELECT upper('w3resource');

Output:

   upper
------------
 W3RESOURCE
(1 row)

PostgreSQL UPPER() function using Column :

Sample Table: employees.

If we want to display the employee_id, first name, and first_name in upper case for those employees who belong to the department which department_id is 100 from employees table , the following SQL can be executed:

SQL Code:

SELECT employee_id,first_name, 
upper(first_name) "Upper case of first_name" 
FROM employees 
WHERE department_id=100;

Output:

 employee_id | first_name  | Upper case of first_name
-------------+-------------+--------------------------
         108 | Nancy       | NANCY
         109 | Daniel      | DANIEL
         110 | John        | JOHN
         111 | Ismael      | ISMAEL
         112 | Jose Manuel | JOSE MANUEL
         113 | Luis        | LUIS
(6 rows)

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