Data Manipulation Language

• SELECT
• INSERT
• UPDATE
• DELETE

SELECT Clause

• https://en.wikipedia.org/wiki/Select_(SQL)

• sql SELECT * FROM Customers;

• sql SELECT DISTINCT Country FROM Customers;

• sql SELECT COUNT(DISTINCT Country) FROM Customers;

• Nested Queries

SELECT Count(*) AS DistinctCountries
FROM (SELECT DISTINCT Country FROM Customers);

DISTINCT Keyword

• use this inside SELECT clause to not show duplicate items

Aliases AS keyword

• https://en.wikipedia.org/wiki/Alias_(SQL)

SELECT column_name AS alias_name
FROM table_name;

SELECT column_name(s)
FROM table_name AS alias_name;

INSERT INTO

INSERT INTO table_name (column1, column2, column3, ...)
VALUES (value1, value2, value3, ...);

UPDATE

SELECT column_names
FROM table_name
WHERE column_name IS NOT NULL;

DELETE

DELETE FROM table_name WHERE condition;

• delete all records

DELETE FROM Customers;