Ram is working in an XYZ company since he is a SQL developer his boss told him to test whether the CRUD(Create Read Update Delete) operation is functional or not. Data given by the boss is : Database Name: Gym Report Table Name: Gym Survey Columns In Table: rid, user_name, email, age, does_gym, total_hours_in_gym So, Ram first created the schema with the following commands: CREATE SCHEMA gym_report ; CREATE TABLE gym_report.gym_survey ( rid INT NOT NULL, user_name VARCHAR(100) NOT NULL, email VARCHAR(100) NOT NULL, age INT NULL, does_gym VARCHAR(45) NULL, total_hours_in_gym INT NOT NULL, UNIQUE INDEX rid_UNIQUE (rid ASC) VISIBLE, UNIQUE INDEX email_UNIQUE (email ASC) VISIBLE, UNIQUE INDEX user_name_UNIQUE (user_name ASC) VISIBLE); Oh No!!! Ram forgot to add the Primary key let's alter and add it: ALTER TABLE gym_report.gym_survey ADD PRIMARY KEY (rid); Now, he decides to add the data : use gym_report; INSERT INTO gym_survey(rid,user_name,email,age,does_gym,total_hours_in_gym) VALUES(345,'Abhilash Khanna','khannaabhi@yahoo.com',23,'Yes',6), (687,'Ayush Rastogi','ayu.rastogi@yahoo.com',28,'Yes',5), (647,'Luna Luna','luna@gmail.com',20,'No',1), (9876,'Asish nayak','nayakashi@hotmail.com',25,'Yes',2), (497,'Nisha Singh','nishasingh@gmail.com',24,'Yes',3), (3476,'Ravi Rathore','rathoreravi@rediff.com',28,'No',1); Then, it's time to read the data: SELECT FROM gym_survey; Now, let's do a bit different thing update the table and check it works UPDATE gym_survey SET total_hours_in_gym=1 WHERE rid=9876; UPDATE gym_survey SET does_gym='No' WHERE rid=9876; SELECT FROM gym_survey; Now, let's try to check if does_gym could be studied in any other way because if the person does gym for less than 2 hours then he/she would not be considered: SELECT rid,user_name,email,age,total_hours_in_gym, CASE WHEN total_hours_in_gym >= 2 THEN 'Yes' ELSE 'No' END AS does_gym FROM gym_survey; Since it works then the does table column doesn't make any requirement so just delete it from the table: ALTER TABLE gym_survey DROP COLUMN does_gym;