Sql Basics | Edureka

INTRODUCTION TO SQL
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DATA AND DATABASE
TABLE
SQL BASIC QUERIES

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WHAT IS SQL?
STRUCTURED
S
Q
L
QUERY
LANGUAGE
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FACTS OF SQL
SQL was developed at IBM by Donald D. Chamberlin and Raymond F.
Boyce in the early 1970s
It was initially called SEQUEL(Structured English QUEry Language)
SQL is a powerful language that uses simple English sentences
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SQL is a Declarative Language

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Portability of
code in SQL is
a prominent
feature
SQL is easy to
learn
With the help
of SQL, one
can create
multiple views
SQL has well-
defined
standards
FEATURES OF SQL

WHAT IS
DATA ?
Data is a collection of facts, figures and vales from
different source.
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WHAT IS
DATABASE ?
Database is a location where data is stored in certain n format
Data from user is
processed
Converted into
meaningful format
Stored as Schema &
Raw Data
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TYPES OF DATABASE
Object Oriented Database
Distributed Database
Operational Database
NoSQL Database
Graph Database
Centralized Database
Cloud Database
1
3
2
4
5
6
7
Relational Database8
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FEW POPULAR DATABASES
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WHAT IS A
TABLE ? ID FIRST_NAME LAST_NAME D.O.B
1 OMAIZ AHMED 13TH MARCH
2 RACHIT KUMAR 16TH OCTOBER
3 SAMHITHA BHAT 12TH
NOVEMBER
4 RAKSHITH KAKTHKAR 22ND OCTOBER
5 PURVI RAVAL 8TH AUGUST
6 VISHNU RAO 15TH
DECEMBER
Table is collection of data in a tabular form
PersonTable
Name
Tuples
Attributes
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TABLE
CONSTRAINTS
IndexUnique
Check
Default
Not Null
Foreign
Key
Primary
Key
06 01
02
0304
05
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Copyright © 2017, edureka and/or its affiliates. All rights reserved.
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SELECT QUERYSYNTAX:
Select column 1,
column2..column N
From Table;
EXAMPLE:
1. Select name From Student;
2. Select * From Student;
Most basic query
used to
manipulate a
database
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SYNTAX:
SELECT column1, column2, ...column N
FROM table_name
WHERE condition;
EXAMPLE:
SELECT FName
FROM Students
WHERE City='Delhi';
WHERE QUERY
1.If we need only
certain records from
the table.
2.Where clause acts
as a Filtering
mechanism.
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SYNTAX: AND OPERATOR
SELECT column1, column2, ...
FROM table_name
WHERE condition1 AND condition2;
EXAMPLE:
SELECT * FROM Student
WHERE FName='John' AND
Lname='Doe';
This operator
displays a record
if all the
conditions
separated by AND
are TRUE
AND
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SYNTAX:
INSERT INTO table_name (column1,
column2,...)
VALUES (value1, value2, value3, ...);
EXAMPLE:
Insert into Student(studentID, FName,
LName, Address, City, Marks)
Values (101, ‘JHON’,’DOE’,’#21, MG ROAD’,
‘Bengaluru’, 550);
If we want to
insert any new
record or data
into a table then
we can use the
INSERT query
INSERT INTO
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SYNTAX: OR OPERATOR
FROM table_name
WHERE condition1 OR condition2;
EXAMPLE:
WHERE FName='John' OR
Lname='Doe';
This operator
displays a record
if any of the
conditions
separated by OR is
TRUE
OR
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SYNTAX: NOT OPERATOR
FROM table_name
WHERE NOT condition;
EXAMPLE:
WHERE NOT Lname='Doe';
This operator
displays a record
if the
condition/condition
s are NOT TRUE
NOT
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SYNTAX:
COUNT(column_name)
FROM table_name
WHERE condition;
EXAMPLE:
SELECT COUNT (studentID)
FROM Student;
COUNT
AGGREGATE
FUNCTIONS
This function
returns the number
of rows that match
specified criteria
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SYNTAX:
SELECT AVG(column_name)
FROM table_name
WHERE condition;
EXAMPLE:
SELECT AVG(Marks)
FROM Student;
AVERAGE
AGGREGATE
FUNCTIONS
This function
returns the
average value of a
numeric column
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SYNTAX:
SELECT SUM(column_name)
FROM table_name
WHERE condition;
EXAMPLE:
SELECT SUM(Marks)
FROM Student;
SUM
AGGREGATE
FUNCTIONS
This function
returns the total
sum of a numeric
column
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SYNTAX:
SELECT MIN(column_name)
FROM table_name
WHERE condition;
EXAMPLE:
SELECT MIN(Marks) AS LeastMarks
FROM Student;
MIN
AGGREGATE
FUNCTIONS
This function
returns the
smallest value of
the selected
column
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SYNTAX:
SELECT MAX(column_name)
FROM table_name
WHERE condition;
EXAMPLE:
SELECT MAX(Marks) AS HighestMarks
FROM Student;
MAX
AGGREGATE
FUNCTIONS
This function
returns the
largest value of
the selected
column
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SYNTAX:
SELECT column_name(s)
FROM table_name
WHERE condition
GROUP BY column_name(s);
EXAMPLE:
SELECT COUNT(StudentID), Fname
FROM Student
GROUP BY Fname;
GROUP BY
Used in SQL to
arrange identical
data into groups
with the help of
some functions
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SYNTAX:
FROM table_name
WHERE condition
GROUP BY column_name(s)
HAVING condition;
EXAMPLE:
SELECT Fname, SUM(Marks)
FROM Student
GROUP BY Fname
HAVING SUM(Marks)>500;
HAVING
Used to place
conditions where
we need to decide
which group will
be the part of
final result-set
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SYNTAX:
FROM table_name
ORDER BY column1, column2, ... ASC|DESC;
EXAMPLE:
SELECT COUNT(StudentID), City
FROM Student
GROUP BY City
ORDER BY COUNT(StudentID) DESC;
ORDER BY
This keyword is
used to sort the
result-set in
ascending or
descending order
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SYNTAX:
SELECT column_names
FROM table_name
WHERE column_name IS NULL;
EXAMPLE:
Select Fname, Lname
From Student
Where Marks IS NULL;
IS NULL
NULL VALUES
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SYNTAX:
SELECT column_names
FROM table_name
WHERE column_name IS NOT NULL;
EXAMPLE:
Select Fname, Lname
From Student
Where Marks IS NOT NULL;
IS NOT NULL
NULL VALUES
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SYNTAX:
UPDATE table_name
SET column1 = value1,
column2 = value2,...
WHERE condition;
EXAMPLE:
UPDATE Student
SET Fname = 'Robert',
Lname= 'Wills'
WHERE StudentID = 101;
The Update command
is used to modify
rows in a table
UPDATE
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SYNTAX:
DELETE FROM table_name
WHERE condition;
EXAMPLE:
DELETE FROM table_name
WHERE condition;
The SQL DELETE
command is used to
delete rows that
are no longer
required from the
database tables
DELETE
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SYNTAX:
FROM table_name
WHERE column_name IN (value1, value2,
...);
EXAMPLE:
SELECT StudentID, Fname, Lname
FROM Student
WHERE City IN ('Delhi', 'Goa',
'Pune','Bengaluru');
IN operator is
used to specify
multiple values
inside the WHERE
clause. It acts as
a short for
multiple OR
IN OPERATOR
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SYNTAX:
FROM table_name
WHERE column_name BETWEEN value1 AND
value2;
EXAMPLE:
SELECT StudentID, Fname,
Lname FROM Student
WHERE Marks BETWEEN 400 AND
500;
BETWEEN operator
will select a
particular value
within the
specified range
BETWEEN
OPERATOR
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SYNTAX:
SELECT column_name AS alias_name
FROM table_name;
EXAMPLE:
SELECT CustomerID AS ID, CustomerName AS
Customer
FROM Customers;
ALLIASES IN
SQL
COLUMN ALIAS
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SYNTAX:
FROM table_name AS alias_name;
EXAMPLE:
SELECT S.Fname, S.LName
FROM Student as S
ALLIASES IN
SQL
TABLE ALIAS
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Sql Basics | Edureka

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