--Use the NOT keyword to select all records where City is NOT "Berlin"

SELECT * FROM Customers

WHERE NOT City = ‘Berlin‘；

--通配符 _

--Select all records where the first letter of the City is an "a" or a "c" or an "s".

SELECT * FROM Customers

WHERE City LIKE '[acs]%';

--Select all records where the first letter of the City is NOT an "a" or a "c" or an "f".

SELECT * FROM Customers

WHERE City LIKE '[!acf]%';

--Use the TRUNCATE statement to delete all data inside a table. 只删除数据，不删除表本身

TRUNCATE TABLE Persons;

--Add a column of type DATE called Birthday.

ALTER TABLE Persons

ADD Birthday DATE;

--Delete the column Birthday from the Persons table.

ALTER TABLE Persons

DROP COLUMN Birthday;