Introduction to SQL

Big Data, SQL & You
By Robert Birch

 It was a language designed for managing
data held in a relational database
management system.
 It was designed by Donald D. Chamberlin and
Raymond F. Boyce of IBM.
 The first prototype of the language came out
in 1974 and since then there has been many
variations of the language.

 It is a great language to use for data mining
and analyzing relationships.
 Many companies use SQL for analyzing data
like banking and healthcare companies.

 Table- contains data
 Row- are information for many types of
categories i.e. company’s name, company’s
industry
 Column-a column contains all the data from
a row for a specific entry. E.g. it would list all
the names of companies.
 Primary Key- is an unique identifier for data
between two tables

 =: 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: To specify multiple possible values for a
column

SELECT Company_Name, Market_Cap
FROM STOCKS
WHERE Industry="Lodging";

SELECT Company_Name, Market_Cap, PE
FROM STOCKS
ORDER BY Market_Cap DESC;

SELECT *
FROM STOCKS
WHERE Market_Cap Between 20 AND 250
ORDER BY Market_Cap;

SELECT Company_Name, ROA
FROM StocksFinancial
WHERE ROA>=0.07;

SELECT * FROM StocksFinancial
WHERE Company_Name IN
(
SELECT Company_Name
FROM Stocks
WHERE market_cap <= 13
);

SELECT * FROM StocksFinancial
WHERE Company_Name LIKE "N*";

SELECT AVG(Market_cap) AS AverageMarketCap
FROM Stocks;

SELECT MAX(Market_cap) AS AverageMarketCap
FROM Stocks;

 DROP STOCKS; ( Delete a table, not
supported by Microsoft Access)

 http://www.w3schools.com/sql/default.asp
 http://stackoverflow.com/
 http://www.sqlcourse.com/index.html

Introduction to SQL

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