SQL k-online material.docx

7/25/2019 SQL k-online material.docx

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SQL

Introduction

Data Types

Number

Char

V archar ( or ) Varchar

Date

Time Stamp

Long

Raw

Long Raw

Lob ( Clob !lob !"ile # NCLob )

$% Number:

o It allows only numeric &alues

o 'aimum sie is *+ digitsSyntax :X Number ( P, (S));

P => It allows how many digits to storeS => Size

Ex :X Number (5,)

,% Char:

o It allows alphanumeric characters ( Numbers - Characters )

o 'aimum sie is ,... !ytes/ CharactersSyntax :X !har( S );

*% Varchar2 ( or ) Varchar2:

o It allows alphanumeric characters


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o 'a sie 0... !ytes/ Characters

o 'emory allocation is dynamicSyntax :X "ar#har( S );

0% Date1

o It is used to store date &alues

o 'a sie is 2 !ytesSyntax : X$ate;

3% Timestamp1

o It is used to store date along with "raction o" seconds%Synta% & X 'imestam;

4% Long1

o It is used to store in"ormation

o 'a sie is , 5!%

o 6nly once we ha&e to use in entire table%Syntax :X ong;

2% Raw1

o It is used to store images

o 'a sie is ,... !ytes%Syntax : X *aw;

+% Longraw1

o It is used to store in"ormation as well as images%

o 'a sie is ,5!Syntax :X ongraw;

7% Lob

o Clob 1

It is used to store huge in"ormation


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'a sie is 0 5!Syntax :X !lob;

o !lob 1

It is used to store images but in the "orm o" binary "ormat%

'a sie is 0 5!Syntax :X +lob;

o !"ile 1

It is used to store the "iles%

'a sie is 0 5!%Syntax :X +ile;

o NCLob1

It is used to store multiple languages ( 8nicode 9ormat )

SQL Statements

DDL ( Data De"inition Language )

D'L ( Data 'anipulation Language )

D:L ( Data :uery Language )

TCL ( Transaction Control Language )

DCL ( Data Control Language )

$% DDL 1

o These are auto commit commands%

o These are session independent%

o These are used to de"ine database ob;ects%

a% Create


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It is used to create the database ob;ectSyntax :!reate table tablename ( !ol-. $atatye, !ol-

$atatye,///);

b%


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a% Insert

It is used to insert the data into table%

=e can insert the data into table in , methods

i% Direct 'ethod1 It is used to insert the data directly to a table%Syntax :Insert into tablename ( !ol-.,!ol- )

"alues ( "al-., "al- )

ii% Re"erence 'ethod 1 It is used to insert the data into tablethorugh prompt%Syntax :Insert into tablename 1alues ( 2!ol-.,2!ol- )3

b% 8pdate

It is used to update the data in a table%Syntax :4date tablename set !ol-.="al-.,!ol-="al-//

where #ondition3

c% Delete

It is used to delete the data in a table%Syntax :$elete rom tablename where #ondition

*% D:L 1

o It is used to retri&e the data "rom a table%Syntax :Sele#t rom tablename;

0% TCL 1

o It is used to sa&e the transactions on a table%

a% Commit

It is used to sa&e the data permanently in a database%

i% Implicit Commit

1 It is applied by the system%

ii% >plicit Commit1 It is applied by the user%

b% Rollbac?


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It is used to cancel the pre&ious transactions%

c% Sa&e @oint

It is used to mar? a speci"ic record%

It is only "or tempary purpose%Syntax :Sa1eoing S.;

d% Truncate

It wor? li?e a Delete - Commit% Syntax :trun#ate tabletablename3

3% DCL 1

o It is used to pro&ide the access to users%

a% 5rant

It is used to pro&ide the permissions to users%

b% Re&o?e

It is used to cancel the permissions to users%

Clauses :

Select Clause

9rom Clause

=here Clause

5roup by Clause

Aa&ing Clause

6rder by Clause

Distinct Clause

$% Select Clause

o It is used to retrie&e the data "rom table%


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,% 9rom Clause

o It is used to retrie&e the data "rom which tables%

*% =here Clause

o It is used to pro&ide the conditions%

o It is used to "ilter the data "rom grouped records%

o It wonBt allow group "unctions and alias names%Syntax :sele#t rom em where detno=.6;

0% 5roup !y Clause

o It is used to ma?e the data into group "ormat%

o It is not possible to pro&ide the group "unctions along with normal columns in a

select statement without using group by clause%Syntax :sele#t rom em grou by detno;

3% Aa&ing Clause

o It is used to pro&ide the conditions%

o It is used to "ilter the data "rom grouped data based on condition%Syntax :sele#t rom em grou by detno ha1ing #ount() > .;

4% 6rder by Clause

o It is used to ma?e the data in orderSyntax :sele#t rom em order by sal;

2% Distinct Clause

o It is used to restrict the duplicate records%Syntax :sele#t distin#t ( emno ) rom em;

Operators


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Special 6perators

Set 6perators

$% * 1 select "rom emp where not deptnoF,.E

*% Relational 6perators ( F H G HF GF F )>$ 1 select "rom emp where deptno HF,.E

0% Special 6perators ( Is In Li?e !etween )

o >$ 1 select "rom emp where comm is nullE

o >, 1 select "rom emp where comm is not nullE

o >* 1 select "rom emp where sal in ( +.. $3.. ,...)E

o >0 1 select "rom emp where sal between $... and ,...E

o >0 1 select "rom emp where ename li?e JKJE

o >3 1 select "rom emp where ename li?e JsBE

N8LL 1

o It is unmeasured &alue

o It is neither J.B or JemptyB

o >&ery null &alue is uniMuely considered by oracle engine%

o


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o I" you calculate any &alue with null "inally we are getting null only%

3% Set 6perators

o !y using set operators we ;oin more than one Muery such Mueries are called

compound Mueries%

o In each o" select statement there must be same number o" columns and same data

type but must not be same sie%

a% 8nion


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Con&ersion 9unctions

5eneral 9unctions


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It wor? similar to that o" round but it wonBt chec? the condition%Syntax :sele#t trun ( .358, ) rom dual;

,% Sting Functions

a% Length ( S )

It is used to display the number o" characters in a gi&en string%Syntax :sele#t length( 9ebs: ) rom dual;

b% Re&erse ( S )

It is used to re&erse the gi&en string%

Syntax : select re&erse ( JebsB ) "rom dualE

c% 8pper ( S)

It is used to con&ert the string into upper characters%Syntax :sele#t uer( 9ebs: ) rom dual;>

d% Lower ( S )

It is used to con&ert the string into lower characters%Syntax :sele#t lower ( 9?+S: ) rom dual;

e% Initcap ( S )

It is used to con&ert the "irst character into upper character in a gi&en

string%Syntax :sele#t init#a ( 9business: ) rom dual;

"% Concat ( S$ S, )

It is used to merge the two strings%


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It is used to remo&e the character "rom right end o" the gi&en string i" the

character is "ound%Syntax :sele#t rtrim ( 9ebsess: , 9s: ) rom dual;

i% Trim

It is used to remo&e the characters "rom both sides in a gi&en string%Syntax :sele#t trim ( 9e: rom 9eebse: ) rom dual;

;% Lpad

It is used to add the character "rom le"t end%Syntax :sele#t lad ( 9ebs:, 5 , 92: ) rom dual;

?% Rpad

It is used to add the character "rom rightend%Syntax :sele#t rad ( 9ebs:, , 92: ) rom dual;

l% Translate ( S C C )

It is used to translate the character wise in a gi&en string i" the character is

"ound%

It is not possible to translate entire string%Syntax :sele#t translate ( 9wel#ome: , 9w: , 9t:) rom dual;

m% Replace ( S S S )

It is used to replace entire string%

It is not possible to replace more than one string%Syntax :sele#t rela#e ( 9e business solutions:, 9business:,

9ebs: ) rom dual;

n% Decode ( Column Condition Do$OOOOO%% Column)

It is used replace more than one string%

It wor?s li?e as a i" condition but it does not allow the relational operators%Syntax :sele#t Aob, de#ode ( Aob, 9manager:, 9mgr:, 9#ler:,

9#l:, 9salesman:, 9sls:, Aob ) rom dual;

o% Case ( when condition then result else de"ault &alue )


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It is used to replace more than one string by using relational operator%Syntax :sele#t #ase when detno=.6 and Aob=:B0N0C?*: then

9mgr: else Aob end A rom em;

p% Substr ( S ' N )

It is used to display the set o" characters "rom a gi&en string%S = StringB = Position

N = No o !hara#ters

Syntax :sele#t substr ( 9wel#ome:, .,< ) rom dual;

M% Instr ( S C ' N )

It is used to display the position number o" a gi&en character%S = String

! = !hara#ter

B = Position

N = D##uran#eSyntax :sele#t instr ( 9wel#ome:, 9e:, ., . ) rom dual;

*% Data 9unctions

a% Sysdate 1

It is used to display the system date%Syntax :sele#t sysdate rom dual;

b% CurrentPDate 1

It is used to display the net day% Syntax :sele#t #urrentEdate romdual;

c%


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"% LastPDay ( Date )

It is used to display the last day o" the gi&en month%Syntax :sele#t lastEday ( sysdate ) rom dual;

ate Formats :

D Number o" day in the wee?

DD Number o" day in the month

DDD Number o" day in the year

DQ 9irst * Characters o" the day S8N

Dy 9irst * Characters o" the day Sun

dy 9irst * Characters o" the day sun

D


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It is used to con&ert system "ormat in to user "ormatSyntax :sele#t toE#har ( sysdate, 9day: ) rom dual;

b% ToPDate ( JCB J"ormatB )

It is used to con&ert user "ormat into system "ormatSyntax :sele#t toEdate ( 9.:, 9$$: ) rom dual;Sele#t toEdate ( 9de#ember:, 9BB: ) rom dual;

c% ToPNumber

It is used to translate a &alue o" char or &archar data type to number

"ormat%Syntax :sele#t toEnumber ( 96: ) rom dual;

3% 5eneral 9untions

a% 8ser # 8id

Select useruid "rom dualE

b% 5reatest # Least

Select greatest ( $,* ) least ( $ , * ) "rom dualE

c% NVL ( Col$ Val )

It is used to handle the null &alues

It wor? li?e as a i" conditionSyntax :sele#t sal, #omm, salFn1l(#omm, 6) rom em;

d% NVL, ( Col$ Val$ Val, )

It is a ad&anced o" n&l

It wor? li?e as a i" then else conditionSyntax :sele#t sal, #omm, n1l ( #omm, 6, .66 ) rom em;

4%


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Synta 1 select ma ( sal ) "rom empE

c%


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o It is used to create primary ?ey on multiple columnsSyntax :#reate table tablename ( sno number(5), sname 1ar#har(6)

rimary ey ( sno, sname );

*% 8niMue

o It is allow only uniMue &alues%

o It does not allow duplicate recordsSyntax :#reate table tablename ( sno number (5) uni7ue );

0% Not Null

o It is allow only not null &alues

o It does not allow null &aluesSyntax :#reate table tablename ( sno number ( 5 ) not null );

3% Chec?

o It is used to chec? the conditionSyntax :#reate table tablename ( sno number ( 5 ), #he# ( sno>6 ));

4% De"ault

o It is used to insert de"ault &aluesSyntax :#reate table tablename ( sno number ( 5 ), grade #har

( ) deault 90: );

2% 9oreign ey

o It is used to maintain a re"erence "rom one table to another table%Syntax :#reate table table. ( sno number (5) rimary ey ) !reate

table table ( dno number ( 5 ), dname 1ar#har(.6), sno number(5)

reeren#es table. (sno)

"oins

Simple oin

Sel" oin

6uter oin

$% Simple oin


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a% >Mui oin

It is used to ;oin two tables based on eMual condition%Syntax :sele#t rom em, det where

em3detno=det3detno;

b% Non >Mui oin

It is used to ;oin two tables based on not eMual conditionSyntax :sele#t rom em, det where em3detno G=det3detno;

,% Se"t oin

a% It is used to ;oin the table itsel"%Syntax :sele#t rom em e., em e where e.3detno=e3detno;

o 6uter oin

a% Le"t 6uter oin

It is used to display the "ull details o" the le"t table and matched records o"

the right table%Syntax :sele#t rom em e,det d where em3detno =det3detno(F);

b% Right 6uter oin

It is used to display the "ull details o" the right table and matched recordso" the le"t table%Syntax :sele#t rom em e,det d where

em3detno(F)=det3detn;

c% 9ull 6uter oin

I" you ;oin le"t and right outer ;oins with union operators such ;oins are

called "ull outer ;oin%Syntax :sele#t rom em e,det d where em3detno(F) =det3detno

4nion

sele#t rom em e,det d where em3detno(F) = det3detno

Synonyms

@ri&ate Synonym

@ublic Synonym


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It is used to hide the owner o" the table%

It wor? li?e as a mirror image o" the tables%

It does not ha&e a own structure%

It is depend on the tables%

=e can possible to create the synonym on tables but we canBt create the synonym


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It is a &irtual table to hide the base table and it wor? li?e a mirror image o" the table%

It doesnBt ha&e own structure

It is not possible to modi"y the structure o" a table by using &iews

=e can de"ine &iew on synonyms and synonym on &iews%

=e can possible to de"ine the &iew on particular columns only%


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2% @artition View

o It is used to de"ine a &iew on compound Mueries%

Syntax :#reate 1iew 1iewEname as 7uery. union 7uery

+% 'aterialied View

o It is one o" the &iew which is ha&ing the own structure%

o It doesnBt allow the dml operations on &iews%

o It is used to store the historical data%

o =e can de"ine the &iew on table which is ha&ing the primary ?ey%

Syntax :#reate materialized 1iew 1iewEname as sele#t rom em;

7% Inline View

o It wor? li?e as a Muery which is ha&ing the Muery in "rom clause or instead o"

table%

Syntax :sele#t rom ( sele#t rom em );

>$ 1 9irst 3 Records 1

o Select "rom ( select emp%rownum r "rom emp ) where rHF3E

>,1 Last 3 Records 1

o Select "rom ( select emp%rownum r "rom emp ) where rG ( select

ma(rownum) #n "rom emp )E

>*1 Random Records1

o Select "rom ( select emp%rownum r "rom emp ) where r in ( $*3 )E

>01 >&en no o" Records 1

o Select "rom ( select emp%rownum r "rom emp ) where mod(r,) F .E

>31 Last Record

o Select "rom (select emp%rownum r "rom emp) where rF ( select count() "rom

emp)E


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$n%exes

Simple Inde

Comple Inde

8niMue Inde

9unctional Inde

!itmap Inde

It is one o" the ob;ect which is used to retrie&e the data "rom the database "astly%

It is used to increase the per"ormance while retrie&e the date "rom the database%

It will ma?e the use o" userPidBs%


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o It is used to create a bit map inde on column%

Syntax :#reate bitma inde% inde%Ename on em ( emno );

Clusters

It is a logical boundary which is used to impro&e the o&erall per"ormance o" the database%

=e can create the cluster on tables but we canBt create on columns%

=e can possible to create a inde on cluster%


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6uter Muery is depend on inner Muery but inner Muery doesnBt depend on

outer Muery%

Syntax :sele#t rom em where emno= ( sele#t rom em );

>$ 1 Display the employees who are wor?ing in research department

Select empnoename "rom emp where deptnoF(select deptno "rom dept

where dnameFUR>S>, 1 Display the employee details who are getting maimum salary

select "rom emp where sal F (select ma(sal) "rom emp)

>* 1 Display the employee details who are getting second maimum

salary

select "rom emp where sal F (select ma(sal) "rom emp where

salH(select ma(sal) "rom emp))

>0 1 Display the employees details to get the particular maimum salary

employee

select "rom emp e where #nF(select count(distinct(sal)) "rom emp where

salGFe%sal)

>3 1 Display the maimum salary emp data in particular deptE

Select "rom emp e where salF(select ma(sal) "rom emp where

deptnoF$.)E

>4 1 Display the maimum salary emp details in dept wise%

Select "rom emp e where salF(select ma(sal) "rom emp group by

deptno)E

>2 1 Display the employees who are reporting to IN5

select "rom emp where mgrF(select empno "rom emp whereenameFUIN5U)

>+ 1 Display the Department details which are ha&ing more than 3

employees

select "rom dept where deptno in (select deptno "rom emp group by

deptno ha&ing count()GF3)


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>7 1 Display the employees who are ha&ing at least , reporting

select "rom emp where mgr in (select mgr "rom emp group by mgr

ha&ing count()GF,) order by mgr

>$.1 Display the dept details which are ha&ing at least * salesmans

select "rom dept where deptno F(select distinct (deptno) "rom emp where

;obFUSS'$$ 1 Display the duplicate records in a table

select "rom emp where rowid not in ( select ma(rowid) "rom emp group

by empno)E

o Co related Sub :uery

In this Muery "irst outer Muery get eecutes based on outer Muery &alue

inner Muery get eecuted and return a &alue and &ery "inally based on the

inner Muery &alue outer Muery &alue will be displayed%

Syntax :sele#t rom em e where .=(sele#t #ount() rom emwhere e3salH=sal); Sele#t rom em e where .=(sele#t #ount()

rom em where e3sal>=sal);

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SQL k-online material.docx