Difference between Decode If else If

What is the main difference between decode and If else if

John Spencer wrote:
does require a context switchOf course there is a context switch. And, yes, they are somewhat costly. But not that costly to avoid them at all costs :)
Say you have this very piece of code (select decode) in your PL/SQL procedure. Let's say the procedure is run one million times per day.
It doesn't take long to see how much time that would take.
declare
    x number := 1;
    y number;
begin
   for i in 1000000 loop
      select decode(x, 1,1, 2,2, 3) into y from dual;
   end loop;
end;
/On my test server the above code took about 20 seconds. That's on one core. Given that some "nothing special" production environment is 16-32 cores these days, the loop effectively took about a second.
There are 86,400 seconds in 24 hours. Which means that, massive thanks to the context switches, we have wasted a whopping *0.001%* of our CPU time.
William Robertson wrote:
The OP asked about the difference between the two, and the fact that they belong to two separate languages strikes me as one rather large difference.Well, trains and buses are two types of public transport.
If the OP asked you what would be the best to catch to get to the city, bus or train, would you tell him that buses are more frequent, but can get stuck in traffic, whereas trains run on dedicated tracks so they are more reliable, but not as frequent, and are also slightly more expensive.
OR, would you tell him that those are different types of transportation and they can't therefore be compared.

Similar Messages

Difference between decode nad replace

can you plz highlight the difference between decode and replace.. am using oracle10g r2 on solaris....
these r the 2 quereies...
select count(DECODE(EMAIL_L,'%@yahoo.com%','%@thoyahoo.com%')) FROM SIEBEL.MAIL
i understand here if EMAIL_L is like @yahoo.com then it returns @thoyahoo.com
select count(REPLACE(EMAIL_L,'%@yahoo.com%','%@thoyahoo.com%')) FROM SIEBEL.MAIL
and here also if EMAIL_L has @yahoo.com then it returns @thoyahoo.com
But when i try and execute each of them i dont get any output in the decode query....
Any explainations???

decode and literals match the exact literals within column not part of string
SQL> select ename,decode(ename,'MI','IM') from emp
2 /
ENAME      DE
SMITH
ALLEN
WARD
JONES
MARTIN
BLAKE
CLARK
SCOTT
KING
TURNER
ADAMS
ENAME      DE
JAMES
FORD
MILLER
14 rows selected.
SQL> select ename,decode(ename,'MILLER','MILLIONAIRE') from emp
2 /
ENAME      DECODE(ENAM
SMITH
ALLEN
WARD
JONES
MARTIN
BLAKE
CLARK
SCOTT
KING
TURNER
ADAMS
ENAME      DECODE(ENAM
JAMES
FORD
MILLER     MILLIONAIRE
14 rows selected.Khurram

Diff between decode and case

Hi
I need small clarification about difference between decode and case
Thanks who visit my thread

And for those people who can't be ar$ed to follow links...
Decode allows for conditional output where the conditions are straightforward matches between values.
Case allows for regular conditions to be used such as greater than, less than etc.
Some of the things done by case can be achieved through decode as well but in a more convoluted manner than simply using case.
;)

Difference between CASE and DECODE

Hi All,
Could you please explain me the basic differences between the CASE and DECODE, which performs fast...?
DECODE is Oracle one, and the CASE is ANSI standard.
As per my knowledge, CASE is a statement and DECODE is a function which was defined in the Standard package.
If we use DECODE, the package has to load first, so it will take a little longer than the CASE. CASE is a simple statement which is ANSI standard.
We can use the CASE in the where clause and can not use the DECODE in the where clause.
Please clarify me and correct me if anything wrong.
Thanks,

IMO, the main important point is the way CASE and DECODE handles NULL
SQL> select ename,comm,
2         decode(comm,300,'A',null,'B','C') dcd,
3         case comm when 300 then 'A'
4                   when null then 'B'
5                   else 'C'
6         end cs
7 from emp;
ENAME            COMM D C
SMITH                 B C --"DECODE treats NULL=NULL. But for CASE, NULL is not equal to "another" NULL
ALLEN             300 A A
WARD              500 C C
JONES                 B C
MARTIN           1400 C C
BLAKE                 B C
CLARK                 B C
SCOTT                 B C
KING                  B C
TURNER              0 C C
ADAMS                 B C
JAMES                 B C
FORD                  B C
MILLER                B C
14 rows selected.
{code}
Edited by: jeneesh on Jun 3, 2013 1:13 PM
Note: in CASE, you should use IS NULL
{code}
case when comm=300 then 'A'
       when comm is null then 'B'
      else 'C'
end
{code}

Pls tell me difference between case and decode

Hi all
pls tell me difference between case and decode
regards

Well not entirely true when you consider working with
sign and decode together. Your example could be
written with decode and sign like this:
decode(sign(sal-1000),1,sal+comm,-1,sal,0)But the case expression reads more easily, I admit.Rob it was just example you considered it special case ,BTW can you do it for me by DECODE function.
SQL> SELECT sal,comm,CASE WHEN sal>1000 AND sal<1300 THEN sal+comm ELSE 0 END
2    FROM emp
3 /
       SAL       COMM CASEWHENSAL>1000ANDSAL<1300THENSAL+COMMELSE0END
      5000                                                          0
      2850                                                          0
      2450                                                          0
      2975                                                          0
      1250       1400                                            2650
      1600        300                                               0
      1500          0                                               0
       950                                                          0
      1250        500                                            1750
      3000                                                          0
       800                                                          0
       SAL       COMM CASEWHENSAL>1000ANDSAL<1300THENSAL+COMMELSE0END
      3000                                                          0
      1100
      1300                                                          0
14 rows selected.Note for OP CASE can be used within PL/SQL witing ORACLE 9i or later release
but DECODE function can only be used within SQL.
Khurram

Difference between the Creative Decoder DDTS-100 & Creative Home Theater Connect DTS-

I've had the Klipsch ProMedia Ultra 5. System for years now for my PC with a Sound Blaster card, and I just got a MacBook.
http://www.klipsch.com/products/details/promedia-ultra-5-.aspx
I've asked on the Klipsch message board about a digital decoder. I was recommended the Creative Decoder DDTS-00
http://us.creative.com/products/product.asp?category=4&subcategory=36&product=9468
but I also found the Creative Home Theater Connect DTS-60 for less money, any idea what the difference between the two would be?
http://us.creative.com/products/product.asp?category=&subcategory=6&product=49

No, for the reason mentionned in the stickies. But since you seems not knowing much on digital sound let me explain.
Digital means it's coded with 0 and , and therefor only cable is sufficient. You might know there is many sound formats for home cinema, like Dolby Digital and DTS. And a digital decoder need to be input a compatible sound stream to be able to decode it. Which means the soundcard MUST be able to convert it's output sound in one receiver compatible format.
Creative cards cannot do this kind of thing.
Another thing: current home theater sound format are limited to 6. (DD-EX and DTS-ES). So you would not be able to achieve more than 6..
THX isn't a sound format, only a certification. The THX calibrator is a must have component to correctly calibrate your speakers to enhance you sound experience.
If you need to have TRUE surround up to 7. channels you don't need to use digital connection because it's simply useless.

Decoding Query Plan XSD (RelOp)- what is the difference between OutputList and DefinedValues

under http://schemas.microsoft.com/sqlserver/2004/07/showplan/showplanxml.xsd
we have
<xsd:complexType name="RelOpType">
<xsd:sequence>
<xsd:elementname="OutputList" type="shp:ColumnReferenceListType"
/>
<xsd:complexType name="RelOpBaseType">
<xsd:sequence>
<xsd:elementname="DefinedValues" type="shp:DefinedValuesListType"
minOccurs="0" maxOccurs="1" />
which is defined as
<xsd:complexType name="DefinedValuesListType">
<xsd:sequence>
<xsd:element name="DefinedValue" minOccurs="0"
maxOccurs="unbounded">
<xsd:complexType>
<xsd:sequence>
<xsd:choice>
<xsd:element name="ValueVector">
<xsd:complexType>
<xsd:sequence>
<xsd:element
name="ColumnReference" type="shp:ColumnReferenceType"
minOccurs="2" maxOccurs="unbounded" />
</xsd:sequence>
</xsd:complexType>
</xsd:element>
<xsd:element
name="ColumnReference" type="shp:ColumnReferenceType"
/>
</xsd:choice>
<xsd:choice minOccurs="0" maxOccurs="1">
<xsd:element
name="ColumnReference" type="shp:ColumnReferenceType"
minOccurs="1" maxOccurs="unbounded" />
<xsd:element
name="ScalarOperator" type="shp:ScalarType"
/>
- 
</xsd:choice>
</xsd:sequence>
</xsd:complexType>
</xsd:element>
</xsd:sequence>
</xsd:complexType>
I can't seem to find a difference between the data in OutputList and DefinedValues. what am I missing? What is DefinedValues supposed to be? TIA.
Mordechai Danielov

Consider this batch (which happened to be in my SSMS window from another forum question):
DECLARE @TempData as TABLE (
Name nvarchar(1111) NOT NULL,
Month char(6) NOT NULL PRIMARY KEY,
CountName int NOT NULL
SELECT Name, convert(datetime, Month + '01')
FROM @TempData
Look at the execution plan as XML and you find:
<RelOp ... PhysicalOp="Compute Scalar">
<OutputList>
<ColumnReference Column="Name" />
<ColumnReference Column="Expr1003" />
</OutputList>
<ComputeScalar>
<DefinedValues>
<DefinedValue>
<ColumnReference Column="Expr1003" />
<ScalarOperator ScalarString="CONVERT(datetime,[Month]+'01',0)">
<Convert DataType="datetime" Style="0" Implicit="false">
<ScalarOperator>
<Arithmetic Operation="ADD">
<ScalarOperator>
<Identifier>
<ColumnReference Column="Month" />
</Identifier>
</ScalarOperator>
<ScalarOperator>
<Const ConstValue="'01'" />
</ScalarOperator>
</Arithmetic>
</ScalarOperator>
</Convert>
</ScalarOperator>
</DefinedValue>
</DefinedValues>
OutputList is the values passed out from the operator to the next guy to the left. DefinedValues are values that are defined in the operator. As you see only one value is defined in the CompuateScalar operator, Expr1003.
For the other operator in the plan, we have:
<OutputList>
<ColumnReference Column="Name" />
<ColumnReference Column="Month" />
</OutputList>
<IndexScan Ordered="false" ForcedIndex="false" NoExpandHint="false">
<DefinedValues>
<DefinedValue>
<ColumnReference Column="Name" />
</DefinedValue>
<DefinedValue>
<ColumnReference Column="Month" />
</DefinedValue>
Here DefinedValues and OutputList are the same. But note that Name is only a defined value in this operator; it is not a defined value in the ComputeScalar operator.
Erland Sommarskog, SQL Server MVP, [email protected]

Whats the difference between these two queries ? - for tuning purpose

Whats the difference between these two queries ?
I have huge amount of data for each table. its takeing such a long time (>5-6hrs).
here whice one is fast / do we have any other option there apart from listed here....
QUERY 1:
SELECT --<< USING INDEX >>
      field1, field2, field3, sum( case when field4 in (1,2) then 1 when field4 in (3,4) then -1 else 0 end)
    FROM
      tab1 inner join tab2 on condition1 inner join tab3 on condition2 inner join tab4 on conditon3
    WHERE
     condition4..10 and
    GROUP BY
      field1, field2,field3
    HAVING
      sum( case when field4 in (1,2) then 1 when field4 in (3,4) then -1 else 0 end) <> 0;
QUERY 2:
   SELECT --<< USING INDEX >>
      field1, field2, field3, sum( decode(field4, 1, 1, 2, 1, 3, -1, 4, -1 ,0))
    FROM
      tab1, tab2, tab3, tab4
    WHERE
     condition1 and
     condition2 and
     condition3 and
     condition4..10
    GROUP BY
      field1, field2,field3
    HAVING
      sum( decode(field4, 1, 1, 2, 1, 3, -1, 4, -1 ,0)) <> 0;
[pre]

My feeling here is that simply changing join syntax and case vs decode issues is not going to give any significant improvement in performance, and as Tubby points out, there is not a lot to go on. I think you are going to have to investigate things along the line of parallel query and index vs full table scans as well any number of performance tuning methods before you will see any significant gains. I would start with the Performance Manual as a start and then follow that up with the hard yards of query plans and stats.
Alternatively, you could just set the gofast parameter to TRUE and everything will be all right.
Andre

What is the difference betwee decode & case function

Hi
What is the difference betwee decode & case function
1.decode can't used in pl/sql 1) case can be user
2.in decode we can't use (>,<,>=) 2) we can use
any other do u have....
thanks in advance....

DECODE works with expressions which are scalar values.
CASE can work with predicates and subqueries in searchable form.
There is one more Important difference between CASE and DECODE
DECODE can be used Only inside SQL statement....
But CASE can be used any where even as a parameter of a function/procedure
Eg:-
SQL> create or replace procedure pro_01(n number) is
2 begin
3 dbms_output.put_line(' The number = '||n);
4 End;
5 /
Procedure created.
SQL> set serverout on
SQL> var a varchar2(5);
SQL> Begin
2 :a := 'ONE';
3 End;
4 /
PL/SQL procedure successfully completed.
SQL> Begin
2 pro_01(Decode(:a,'ONE',1,0));
3 End;
4 /
pro_01(Decode(:a,'ONE',1,0));
ERROR at line 2:
ORA-06550: line 2, column 9:
PLS-00204: function or pseudo-column 'DECODE' may be used inside a SQL
statement only
ORA-06550: line 2, column 2:
PL/SQL: Statement ignored
SQL> Begin
2 pro_01(case :a when 'ONE' then 1 else 0 end);
3 End;
4 /
The number = 1
PL/SQL procedure successfully completed.Message was edited by:
Avi
Message was edited by:
Avi

The difference between an iphone and an ipod touch?

i want to know if the difference between an iphone and an ipod touch is just that the iphone is like a phone that has internet and is a phone. or what else is it?

The iPhone includes the same as an iPod Touch but also includes a phone, a camera, and a GPS radio.
In addition to having internet access via wi-fi, the iPhone also has internet access via the cellular network, so as long as you have cellular reception with the iPhone, you have access to the internet in addition to having access via an available wi-fi network.

Getting Big Headache, What is difference between Flash Lite 3.1 and Flash Player 7

Hello, I am asking questions about the two similar yet different programs for Pocket PC version only:
1) Which came first, Flash Lite 3.1 or Flash Player 7?
2) If I have both in my Pocket PC, will there be product incompatibility?
3) What is the difference between Flash Lite 3.1 and Flash Player 7.
4) I have a Flash Lite 3.1 but uninstall information says "Flash Lite 3.1 for Opera Mobile", did you releaase this? Is this an illegal copy? A developer's copy?
*I don't know exactly where I got it, but I got it from the HTC developer's forum: XDA-developers.com
*I also use Opera mobile, a web browser for Pocket PC's.
5) What is difference between Flash Lite 3.1 and Flash Lite 3.1 for Opera? Is the only difference is that Flash Lite Supports everything flash related, while Flash Lite Opera supports only flash in opera?
Hi, I don't expect all answers, but I hope someone or someone from adobe support can clear some things up for me.

The program under my "remove programs" list is specifically called "Adobe Flash Lite for Opera". The XDA forums people said along time ago that it was Flash Lite, and kept calling it Flash Lite, and not Flash Player 7.
Now what about this:
http://www.adobe.com/products/flashlite/version/
The table shows the differences between FP 7 SDK, FL 2.1, and FL 3.1. And it's quite obvious that FL 3.1 has way more features than Flash Player 7. What does SDK mean? And why are you telling me FP 7 has more features?
With this information, can you or anyone else provide any more details and clarification?

Difference between abap object and function

hi all,
i read the book on abap object of the difference between abap object and classical abap.
i know that there is only 1 instance of a specific function group but somehow i still not so clear why subsequent vehicle cannot use the same function. i also can use the do and loop to call the function? if cannot then why?
hope can get the advice.
thanks
using function *********
function-pool vehicle.
data speed type i value 0.
function accelerate.
speed = speed + 1.
endfunction.
function show_speed.
write speed.
endfunction.
report xx.
start-of-selection.
*vehicle 1
call function 'accelerate'.
call function 'accelerate'.
call function 'show_speed'.
*vehicle 2
*vehicle 3
*****abap object*******
report xx.
data: ov type ref to vehicle,
         ov_tab type table of ref to vehicle.
start-of-selection.
do 5 times.
create object ov.
append ov to ov_tab.
enddo.
loop at ov_tab into ov.
do sy-tabix times.
call method ov->accelerate.
enddo.
call method ov->show_speed.
endloop.

Hi
Now try this:
REPORT ZTEST_VEHICLEOO .
PARAMETERS: P_CAR   TYPE I,
            P_READ TYPE I.
*       CLASS vehicle DEFINITION
CLASS VEHICLE DEFINITION.
PUBLIC SECTION.
    CLASS-DATA: MAX_SPEED   TYPE I,
                MAX_VEHICLE TYPE I,
                NR_VEHICLES TYPE I.
    CLASS-METHODS CLASS_CONSTRUCTOR.
    METHODS CONSTRUCTOR.
    METHODS ACCELERATE.
    METHODS SHOW_SPEED.
    METHODS GET_SPEED EXPORTING E_SPEED TYPE I.
PRIVATE SECTION.
    DATA: SPEED      TYPE I,
          NR_VEHICLE TYPE I..
ENDCLASS.
*       CLASS vehicle IMPLEMENTATION
CLASS VEHICLE IMPLEMENTATION.
METHOD CLASS_CONSTRUCTOR.
    NR_VEHICLES = 0.
ENDMETHOD.
METHOD CONSTRUCTOR.
    NR_VEHICLES = NR_VEHICLES + 1.
    NR_VEHICLE = NR_VEHICLES.
ENDMETHOD.
METHOD ACCELERATE.
    SPEED = SPEED + 1.
    IF MAX_SPEED < SPEED.
      MAX_SPEED   = SPEED.
      MAX_VEHICLE = NR_VEHICLE.
    ENDIF.
ENDMETHOD.
METHOD SHOW_SPEED.
    WRITE: / 'Speed of vehicle nr.', NR_VEHICLE, ':', SPEED.
ENDMETHOD.
METHOD GET_SPEED.
    E_SPEED = SPEED.
ENDMETHOD.
ENDCLASS.
DATA: OV     TYPE REF TO VEHICLE,
      OV_TAB TYPE TABLE OF REF TO VEHICLE.
DATA: V_TIMES TYPE I,
      FL_ACTION.
DATA: V_SPEED TYPE I.
START-OF-SELECTION.
DO P_CAR TIMES.
    CREATE OBJECT OV.
    APPEND OV TO OV_TAB.
ENDDO.
LOOP AT OV_TAB INTO OV.
    IF FL_ACTION = SPACE.
      FL_ACTION = 'X'.
      V_TIMES = SY-TABIX * 2.
    ELSE.
      FL_ACTION = SPACE.
      V_TIMES = SY-TABIX - 2.
    ENDIF.
    DO V_TIMES TIMES.
      CALL METHOD OV->ACCELERATE.
    ENDDO.
    CALL METHOD OV->SHOW_SPEED.
ENDLOOP.
SKIP.
WRITE: / 'Higher speed', VEHICLE=>MAX_SPEED, 'for vehicle nr.',
            VEHICLE=>MAX_VEHICLE.
SKIP.
READ TABLE OV_TAB INTO OV INDEX P_READ.
IF SY-SUBRC <> 0.
    WRITE: 'No vehicle', P_READ.
ELSE.
    CALL METHOD OV->GET_SPEED IMPORTING E_SPEED = V_SPEED.
    WRITE: 'Speed of vehicle', P_READ, V_SPEED.
ENDIF.
Try to repeat this using a function group and I think you'll undestand because it'll be very hard to do it.
By only one function group how can u read the data of a certain vehicle?
Yes you can create in the function group an internal table where u store the data of every car: in this way u use the internal table like it was an instance, but you should consider here the example is very simple. Here we have only the speed as characteristic, but really we can have many complex characteristics.
Max

Can Oracle be forced to use the spatial index for sdo_filter in combination with an or clause? Difference between Enterprise and SE?

We’re seeing the following issue: sql - Can Oracle be forced to use the spatial index for sdo_filter in combination with an or clause? - Stack Overflow (posted by a colleague of mine) and are curious to know if this behaviour is due to a difference between standard and enterprise, or could we doing something else wrong in our DB config.?
We have also reproduced the issue on the following stacks:
Oracle SE One 11.2.0.3 (with Spatial enabled)
Redhat Linux 2.6.32-358.6.2.el6.x86_64 #1 SMP Thu May 16 20:59:36 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux
11.2.0.3.0 Standard Edition and 11.2.0.4.0 Standard Edition (both with Spatial enabled)
Microsoft Windows Server 2003R2 Standard x64 Edition
However, the SQL works fine if we try it on Oracle 11.2.0.3.0 *Enterprise* Edition.
Any help or advice would be much appreciated.
Kindest Regards,
Kevin

In my experience sdo_filter ALWAYS uses the spatial index, so that's not the problem. Since you did not provide the explain plans, we can't say for sure but I think yhu is right: Standard Edition can't use the bitmap operations, and thus it'll take longer to combine the results of the two queries (because the optimizer will surely split this OR up in two parts, then combine them).
BTW: when asking questions about queries here, it would be nice if you posted the queries here as well, so that we do not have to check another website in order to see what you are doing. Plus it will probably get you more answers, because not everyone can be bothered to click on that link. It would also have been nice if you had posted your own answer on the other post here as well, because my recommendation would have been to use union all - but since you already found that out for yourself my recommendation would have been a little late.

What is the difference between the three network carriers and if i am to use iPhone 5 in Bangladesh, which network carrier should i choose?

I had one confusion about the network carrier of which one to chose. Actually I do not know the difference between them. Are they related to some sort of sim cards? I would be grateful if anyone could help me to get away this confusion.

Unless we are in Bangladesh, nobody here can really help you with this. If you purchased the phone there, you need to do that research for yourself. You are the one who is there and on the spot so noone else can really help you with that.
You need to contact the available carriers in your area and see what the differences are for yourself.
The phone companies supply you with the appropriate sim cards when you take out a contract with them.
Also, where did you purchase the phone from in the first place and is it an unlocked phone? If the phone is not unlocked, then it won't work.

Difference between iteratior and List Iterator

Difference between iteratior and List Iterator

Ravikumar:
You have already posted something quite similar to this posting here: http://forum.java.sun.com/thread.jspa?threadID=735377
While I cannot speak for everyone else here, I personally find your approach rather rude and inconsiderate. The manner in which you are posting these questions implies that you not only do not recognize that there is work involved in answering them but that you do not sufficiently understand them in such a manner as to be able to phrase them coherently.
I expect that you are attempting to do your homework by exploiting the helpful people on this forum rather than by learning the material in question. If I am mistaken as to your intentions, please inform me and I will apologize to you. However, I find it difficult to believe that anyone would have such poor forum etiquette as not to realize that posting a "question" in the form of a topic statement is impolite.
There are many fine people here who will assist you in learning and applying Java; I have relied upon their assistance on multiple occasions and found it indispensible. But you are far more likely to receive a helpful response (at least from me) if you take the time to express your questions more fully and (especially) to learn the material.
Cheers and happy learning.

Difference between Decode If else If

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