SQL Syntax - Part1

TABLE NAME : 'Customers' 

• SELECT
• Used ALMOST ALWAYS! Select the specific columns you want or '*' for every columns in a table

SELECT column_name1, column_name2

FROM table_name1;

or 

SELECT *

FROM table_name1;

-- everything!

• DISTINCT
• Select only the different(distinct values) among many duplicate

SELECT DISTINCT column_name, column_name
FROM table_name1;

• WHERE
• filter records; extract clause is used to extract only a specified criterion

SELECT column_name, column_name

FROM table_name1
WHERE column_name operator value;

ex) SELECT *
FROM Customers
WHERE Country='Mexico';

SELECT *
FROM Customers
WHERE ID=5;
-- you do not need single quotes('') in a number

Operators in the WHERE Clause

• = : equal
• <> / != : not equal
• > : greater than
• < : less than
• >= : greater than or equal
• <= : less than or equal
• BETWEEN: Between an inclusive range
• LIKE: Search for a pattern
• IN : multiple possible values including 'the value'

• AND
• Satisfies both the first AND second condition

SELECT * FROM Customers
WHERE Country = 'Germany' AND City = 'Berlin';

• OR
• Satisfies EITHER the first OR second condition

SELECT * FROM Customers
WHERE City = 'London' OR City = 'Berlin';

• Combining AND & OR

SELECT * FROM Customers
WHERE Country = 'Germany' AND (City = 'London' OR City = 'Berlin');

• Order By
• Sort the data by one or more columns
• could be ascending | descending

SELECT * FROM table_name
ORDER BY column_name ASC|DESC,  column_name ASC|DESC;

SELECT * FROM Customers
ORDER BY Country ASC, City DESC;

• INSERT INTO
• Insert new records in a table

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

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

INSERT INTO Customers(CustomerName, ContactName, Address, City, PostalCode, Country)
VALUES('Sue', 'Park', 'TeheranRo', 'Seoul', '15320', South Korea)