sql where like case insensitive code example

Example 1: sql like case sensitive

-- Postgresql case insensitive:
SELECT * FROM people WHERE name ILIKE 'JOHN'
-- John
-- JOHN
-- john

Example 2: how to make case insensitive in sql

-- find everyone with  first_name contains d case insensitive manner
Make everthing either lower or upper case

SELECT FIRST_NAME , LAST_NAME 
FROM EMPLOYEES 
WHERE LOWER(FIRST_NAME) LIKE '%d%' ;