Getting Started with SQL Language.pptx

MagnaDataSolutions.com
Getting started with the
SQL Language
Cecilia Brusatori
Magna Data Inc

Cecilia Brusatori
ready
Founder and CEO of Magna Data inc
Data Analytics Solutions and Corporate Training
University Graduate Degree in Computer Science
& Engineering
Tech Community Leader & Organizer in South
Florida US
Proudly Nerd - Always Learning - Naturist –
Love Animals, good Books & the Beach
Entrepreneur - Consultant, Trainer, Speaker
Miami/Fort Lauderdale Area

Agenda
 DBs Concepts & Terminology
 Intro to SQL Language
 DML Syntax: SELECT, UPDATE, INSERT, DELETE
 Exploring SELECT
 WHERE, Operators
 Aggregations
 Group By, Having
 Types of Joins

Databases
Concepts & Terminology

RDBMS
 Relational Database Management Systems
 Software that provides Users and
Applications, with processes to: Define,
Create, Manipulate and Share (Relational)
Databases
User Applications
RDBMS Server
…

Relational Databases
 Database > Tables > Rows > Columns
1
1..*
1
1
0..*
1
0..*
0..*
 ERD: display entities
and how they are
related
 Primary Keys (PK):
Uniquely identifies
each record in a table
 Foreign Keys (FK):
refers to the Primary
Key in another table

Introduction to SQL

About the SQL Language
 Structured Query Language
 SQL / SEQUEL (Structured English Query Language)
 Interact with Relational Databases
 Comes from Relational Algebra & Calculus.
Codd, Chamberlin & Boyce.
SQL history by Chamberlin, here: https://ieeexplore.ieee.org/document/6359709
 Declarative Language vs Procedural/imperative language
 SQL Standard defined by ANSI (American National Standards Institute)
 Vendors variations and extensions.

Extensions to SQL Language
Add Procedural Programming Language Functionality (Functions,
Cursors, arrays, loops, Control of Flows, etc)
Oracle PL/SQL Procedural Language/SQL
Microsoft SQL Server T-SQL Transact-SQL
Informix SPL Stored Procedural Language
MySQL SQL/PSM SQL/Persistent Stored Module
PostgreSQL PL/pgSQL Procedural Language/PostgreSQL SQL
SAP R3 ABAP Advance Business Application Programming
MariaDB SQL/PSM SQL/Persistent Stored Module

Language Classifications
SQL
DDL
Create, Alter,
Drop, Rename
DML
Select, Insert,
Update, Delete
DCL
Grant,
Revoke, Deny
RDBMS Server

DML SYNTAX

DML - Syntax
SELECT Column1, Column2, … FROM Table1
SELECT Column1, Column2, … FROM Table1 WHERE Condition
INSERT INTO Table1 (Column1,Column2,…) VALUES(Value1,Value2,…)
UPDATE Table1 SET Column1=Value1, Column2=Value2,…
UPDATE Table1 SET Column1=Value1, Column2=Value2,… WHERE Condition
DELETE FROM Table1
DELETE FROM Table1 WHERE Condition

DML – Syntax - Examples
• SELECT FirstName, LastName, email, DoB, FROM Customer;
• UPDATE Customer SET LastName=‘Smith’ WHERE CustomerID=123;
• INSERT INTO Customer(FirstName, LastName, email)
VALUES (‘Jane’, ’Doe’, ’Jdoe@gmail.com’);
• DELETE FROM Customer WHERE CustomerID = 123;

Interaction Example
SQL Statement
SELECT * FROM [Orders]
User/App
Microsoft
SQL Server
1
2 3
4

Let’s Explore SELECT
DML

SELECT
 Selects Data and Returns a Result-set. (result table)
 * Brings all fields
 Specify Columns
SELECT * FROM Table1;
SELECT Column1, Column2, …, ColumnN FROM Table1;

ORDER BY
 Sorts the Result_set by the Column(s) specified.
 ASC, DESC
SELECT Column1, Column2
FROM Table1
ORDER BY Column1 DESC;

WHERE Clause
SELECT Column1, Column2
FROM Table1
WHERE Condition;
Conditionals:
 Boolean operators/Logical Operators AND, OR, NOT
 Comparison operators:
 =,<>,<=,>. Some DBs inequality: !=,^=,<>
 ANY/SOME
 EXISTS
 LIKE
 BETWEEN
 IS NULL

NULL values
 Represents “Nothingness”. It is not a Value. It is an Empty field
 Origin: Value not entered/recorded
 May affect results (Example with AVG)
 Used with operators IS/NOT: IS NULL, IS NOT NULL

Aggregations
Function Description
COUNT() Counts elements in a column. COUNT (*) counts tuples.
SUM() Returns the Summarization of all values in a column.
AVG() Returns the Average from values in a column.
MAX() Returns the Maximum value in a column.
MIN() Returns the Minimum value in a column

GROUP BY
Create Subgroups of Tuples
SELECT Column1, SUM(Column2)
FROM Table1
GROUP BY Column1;

HAVING
 HAVING clause: contains conditions on aggregates
 Specifies a search condition for Groups
SELECT Column1, SUM(Column2)
FROM Table1
GROUP BY Column1
HAVING SUM(Column2) >10000;

Syntax Evaluation Order (Ms SQL Server)
1
2
3
4
5
6

Types of JOINS
Natural Join,
INNER Join,
Join
Left Outer Join Right Outer Join
Full Outer Join

Inner Join
SELECT *
FROM Table1 T1 INNER JOIN
Table2 T2 ON (T1.ID=T2.ID)

Left Outer Join
SELECT *
FROM Table1 T1 LEFT JOIN

Right Outer Join
SELECT *
FROM Table1 T1 RIGHT JOIN

Full Outer Join
SELECT *
FROM Table1 T1 FULL OUTER JOIN

Oracle
SQL

Resources
 Practice website:
https://www.w3schools.com/sql/trysql.asp?filename=trysql_select_all
 Oracle:
https://docs.oracle.com/en/database/oracle/oracle-
database/19/sqlrf/Introduction-to-Oracle-SQL.html
 PostgreSQL:
https://www.postgresql.org/docs/current/sql.html
 Ms SQL Server:
https://learn.microsoft.com/en-us/training/paths/get-started-querying-with-
transact-sql/
 MySQL:
https://dev.mysql.com/doc/refman/8.0/en/sql-statements.html
 IBM DB2:
https://www.ibm.com/docs/en/db2-for-zos/11?topic=db2-sql

THANK YOU!
Connect to me at: Cecilia@MagnaDataSolutions.com
/CeBrusa
@CeBrusa
@MagnaDatainc
@MagnaDatainc
/company/magnadatainc
https://magnadatainc.com
Presentation:
www.MagnaDataSolutions.com/intro-to-sql-language

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