SQL Alter

Question 1

Add column

Answer 1

ALTER TABLE users ADD COLUMN email TEXT;

Question 2

Modify column (datatype)

Answer 2

ALTER TABLE users MODIFY COLUMN age INTEGER;

Question 3

Drop Column

Answer 3

ALTER TABLE users DROP COLUMN email;

Question 4

Rename Table

Answer 4

ALTER TABLE users RENAME TO customers;

Question 5

Modify (add/remove) Column Constraint

Answer 5

ALTER TABLE table_name ADD CONSTRAINT constraint_name constraint (column_name);
ALTER TABLE table_name DROP CONSTRAINT constraint_name;

Question 6

Modify column (name)

Answer 6

ALTER TABLE table_name
RENAME COLUMN old_column_name TO new_column_name;