SQL

Question 1

How do you drop a table?

Answer 1

DROP TABLE example

Question 2

How do you drop a column?

Answer 2

ALTER TABLE example
DROP COLUMN examplecolumn

Question 3

How do you create a table?

Answer 3

CREATE TABLE example {
ID int AUTO INCREMENT,
Name varChar(255),
CONSTRAINT example_pk PRIMARY KEY (ID),
City varChar(255)
};

Question 4

How to add columns?

Answer 4

ALTER TABLE example
ADD email varchar(255)

Question 5

how to insert rows?

Answer 5

INSERT INTO example (id, name) VALUES (id, name)

Question 6

how to update info

Answer 6

UPDATE example
SET contactName = “Glen”
WHERE customerID = 1;

Question 7

When and how to use having?

Answer 7

use having for arithmetic functions e.g. finding values where the sum of something is greather than an amount

SELECT Count(customers), Country
FROM example
GROUP BY country
HAVING Count(customers) > 5