Set - 1

Question 16 :

How would you delete a column?

Answer :

ALTER TABLE techpreparation_answers DROP answer_user_id.


Question 17 :

How would you change a table to InnoDB?

Answer :

ALTER TABLE techpreparation_questions ENGINE innodb;


Question 18 :

When you create a table, and then run SHOW CREATE TABLE on it, you occasionally get different results than what you typed in. What does MySQL modify in your newly created tables?

Answer :

1. VARCHARs with length less than 4 become CHARs
2. CHARs with length more than 3 become VARCHARs.
3. NOT NULL gets added to the columns declared as PRIMARY KEYs
4. Default values such as NULL are specified for each column


Question 19 :

How do I find out all databases starting with 'tech' to which I have access to?

Answer :

SHOW DATABASES LIKE 'tech%';


Question 20 :

How do you concatenate strings in MySQL?

Answer :

CONCAT (string1, string2, string3)