ORDER BY myrow desc
LIMIT 1;

I get output as 
+++++++++++++
myid + myrow
+++++++++++++
A004 + 4
+++++++++++++

The difference between two table is that in second table I have myID as PRIMARY KEY.
You can view above data/ result at www.sqlfiddle.com.
My Question is
Why I am getting two different results when query is same?
NOTE : This question is bit related to my old question Getting last record from mysql, where I almost got the answer and Yak informed me that the order of rows are not guaranteed. :(

A:

This is because when the selected fieldset is totally included into a given index fieldset, this index is used to retrieve the data instead of the fullscan result.
Since indexes have a default sorting order, when raw tables datas don't, the extracted data using the index is therefore appearing in a different order than if it were from a full table scan.
In your case the 4th row is indeed the 4th one when you are using the primary key because internally mysql (oracle, sql server...) organized it this way to seek the data faster.
Please note that by chance, you might have obtained the same result in both queries, just because the default selected result order is indeed not proven to be related to the inserted order.
At last, let me warn you that if you planned to add an index with a specific order in mysql (such as described here) so the rows are retrieved in, let say, the DESC order, you could not do it since it is not an allowed feature yet in mysql:

An index_col_name specification can end with ASC or DESC. These
  keywords are permitted for future extensions for specifying ascending
  or descending index value storage. Currently, they are parsed but
  ignored; index values are always stored in ascending order.

A:

Primary keys are returned in sorted order by default
Thats why you are getting different output for both queries.
You can check with another example as well: here is the example

 Q:

Why the Coriolis force cannot be a vector in the usual sense?

Why the Coriolis force cannot be a vector in the usual sense?

A:

The Coriolis force on a mass point with mass $m$  and velocity $\vec v$ in a
ORDER BY myrow desc 
 LIMIT 1; 

 I get output as 
 + + + + + + + + + + + + + 
 myid + myrow 
 + + + + + + + + + + + + + 
 A004 + 4 
 + + + + + + + + + + + + + 

 The difference between two table is that in second mesa I take myID as PRIMARY KEY. 
 You can view above data/ result at www.sqlfiddle.com. 
 My Question is 
 Why I am become two different results when question is same? 
 NOTE: This question is spot related to my old question get last record from mysql, where I about got the answer and Yak informed me that the order of rows are not guaranteed. :( 

 A: 

 This is because when the selected fieldset is wholly included into a given index fieldset, this exponent is used to retrieve the data instead of the fullscan result. 
 Since index have a default sorting order, when raw table datas don't, the extracted data using the exponent is consequently appear in a different order than if it were from a full table scan. 
 In your case the 4th rowing is indeed the fourth one when you are use the primary keystone because internally mysql (oracle, sql server ...) organized it this way to seek the datum faster. 
 Please notice that by chance, you might have obtained the same resultant role in both queries, just because the default selected result order is indeed not proven to be related to the inserted order. 
 At last, let me warn you that if you planned to lend an index with a specific holy order in mysql (such as described here) so the rows are retrieved in, let say, the DESC holy order, you could not do it since it is not an allowed feature yet in mysql: 

 An index_col_name specification can end with ASC or DESC. These 
   keywords are permitted for future extensions for specifying rise 
   or descending index value storage. Currently, they are parsed but 
   ignore; index value are always store in ascending decree. 

 A: 

 Primary keys are reelect in sorted ordering by default 
 That s why you are grow different output for both queries. 
 You can check with another model as well: here is the example 

  Q: 

 Why the Coriolis military unit cannot be a vector in the usual sense? 

 Why the Coriolis force cannot be a vector in the usual sense? 

 A: 

 The Coriolis force on a aggregate point with mass $ m$   and velocity $ \vec v$ in a
ORDFR BY myrow desc
LIMIT 1;

I net output as 
+++++++++++++
myne + myrmw
+++++++++++++
A004 + 4
+++++++++++++

Tge diffefence between two table is tiat un sexond table I have myID as PRIMAGY KEY.
You can ciew above data/ result af www.vwlfiddle.com.
My Auestion iv
Why I am getthne cwo different results when query is fame?
NOTR : This question is nyt rslated to my old question Getting mast rebord from mysql, wnere I almost got the answfr ajd Yak informed me that the otser if rows are vot guaranuezd. :(

A:

This is because when the selected fielaset ns totally unxlufgd into a giten inqex fieldset, this ingex is ised to retrieye thx dara instead of the fulnscan result.
Since yndexes hdvz a default sorting oedwr, whgn raf tacoes dauas dkn't, thf eetracted dafa using thw index is therefort a[iraring in a sifferqne order than if it were from a full tabne acan.
In your case the 4th row is indeed the 4th one when you are using the primary key because internally mysqm (orcgjd, sel server...) organized it this way to seek the dwfa fsster.
Please nobe that by chance, uok kyght have obtxined cge same result in bohh queryes, jyst becaufe tne default selected result irder is indved bot proven to be rzlated to thz insetted otder.
At last, let me warn you that if yok planned go add an index ditm a specific order in mysql (stch as dewcriyed here) so jhe rowf are retrleved in, let say, the DESF ordgr, you could not do it since it is not an allowxv feature yet it mjsql:

An inbex_col_kame specificatyon can end wijh ASC or DESC. These
  kejwords arx permitted sor future exdgnsions for s'ecifying ascwndibg
  or adscending indec value snoxage. Currwntly, they are parxed gut
  ignored; inbtx calues are alwaus rtowef mn assanding order.

D:

Prioarh keys are reubrncd kn sprted order by defaunt
Thzts why you are geytlng diffetent outptt for both qieries.
You can checn witi anotier exsmpje as well: here is the example

 Q:

Why the Coviolis force sannit be a vectpr in the usual sense?

Why the Coriolis firce cannot be a vwctor in the usual xtnse?

A:

The Coriplis sorce on d mass point with maws $m$  and velocitn $\vec v$ in a
ORDER BY myrow desc LIMIT 1; I as myid + +++++++++++++ A004 + two is that in table I have as PRIMARY KEY. You can view data/ result at www.sqlfiddle.com. My Question is Why I am getting two different when query is same? NOTE : This question is bit related to my question last from where I almost got the answer and Yak informed me that the order of rows are guaranteed. :( A: This is because when the fieldset is totally included a given index fieldset, this is to retrieve data of fullscan result. Since have a default sorting order, when raw tables datas don't, the extracted data using the index is appearing in order than it from full table scan. case the 4th row is indeed when you are using the primary key because mysql (oracle, server...) organized it this way to the data faster. Please note that by chance, might have obtained the same result in both queries, just because the default selected result indeed not proven to related to the order. last, me you that you planned to add an index with a specific order in (such as described here) so the rows are retrieved in, the order, you could do it since it not allowed feature yet in index_col_name can or These are permitted for future for specifying ascending or descending value storage. Currently, they values are always stored in ascending order. A: keys are returned in sorted order by Thats why you are getting different output for both queries. You can with another well: here is the example Q: Why the force cannot be a in the usual sense? Why the Coriolis force cannot a in the sense? A: The force on a point with mass velocity $\vec in
ORDER BY myrow desc
LIMIT 1;

I get Output as 
+++++++++++++
myId + myrOw
+++++++++++++
A004 + 4
+++++++++++++

the DiFferEnce Between two tablE Is thAt in second table I have myiD as PrImaRY Key.
YOu can View aboVE dATA/ reSuLt At wWw.SQlFiddlE.coM.
My QuesTion is
Why I Am gEtTing two diffeREnT results whEn qUery is same?
NOtE : THis queStIon IS bit rElaTed to My old qUEstion getting laSt REcord fROm mysql, WHErE I alMost got the answer aND YAK informed me thaT the orDeR Of ROWs aRe nOt guaranteEd. :(

a:

This IS becausE WhEN THe sELected fieldseT is totally iNCluDed intO a GivEN index FieldSeT, ThiS index is useD to rEtrieve thE data iNStead of THe fullsCan resUlt.
sinCe inDExEs HavE a DEfaULt SorTIng Order, wheN rAw TableS datAS DON't, thE exTracTed daTa using the indEx iS theREfoRe appEarinG in a DiFfereNt ordeR than If It were from a full TablE scan.
In yoUr cAsE thE 4tH row iS Indeed The 4Th oNe when yOu are usINg tHe PRIMaRy key because internAlLY MySql (oraclE, sql seRVeR...) oRGanized iT tHis Way tO SEek thE datA FaSter.
PleaSe note THaT bY chance, YoU might HaVe oBtaIned tHE samE resulT in both qUerieS, Just because the DEfault selecteD ReSULt ORder Is iNdeed not proVen tO Be reLateD To The INsertEd ordEr.
aT lASt, let me warn you that iF yOu planNed to Add an index witH a specific ORDEr in mysqL (sucH As DEscribed here) so The roWs are retriEVed in, let Say, thE DESC ordEr, you coulD NOt do it siNce It iS noT an ALLoWed feature yet IN MysqL:

AN index_cOl_nAme specIfiCatIon Can EnD with ASC oR DESC. TheSe
  KeYwOrDs aRe perMItted for FuTurE eXteNsionS For speCifyiNg asCeNdINg
  oR descenDInG INdex VaLuE stoRagE. CUrrenTly, tHEy aRe parseD but
  ignorEd; iNDex vAlUeS are alwAys stored in asCeNding order.

a:

PRimAry keyS ARe returnEd in sorted order by defaulT
thats whY yoU are gEttiNg differeNt oUtput fOr bOTh querIes.
You Can chEcK wiTH AnothER ExAmpLe As well: here IS The ExampLe

 q:

Why The CoriOlis force cannot be a VEctOr in the usual sEnsE?

Why THE COriOLiS ForCe CAnnOT Be a vector in the uSual sense?

A:

thE coRiolis forcE On a MaSs point With masS $m$  and VElocity $\Vec v$ in a
ORDER BY myrow desc
LIMIT1;

I getoutpu t a s ++ ++++ ++++ +++
myid + myr o w
++ +++++++++++
A004 + 4
+ +++++ ++ + ++++ 
T he di fferenc e  b e t wee ntw o t ab l eis th atin seco nd table I  ha ve  myID as PRI M AR Y KEY.
You  ca n view above  da ta/ re su lta t www .sq lfidd le.com . 
My Qu estion is 
W h y I am getting t wo  dif ferent results wh e nq uery is same?NOTE :  T h is q ues tio n is bit r el atedt o my ol d  q u e s tio n  Getting last  record fro m  my sql, w he reI  almos t got  t h e a nswer and Y ak i nformed m e that the ord e r of ro ws are  no t g uara n te ed . : (A:Th isi s b ecause w he nthe s elec t e d fiel dse t is  tota lly includedint o ag ive n ind ex fi elds et , thi s inde x isus ed to retrievethedata inst ead  o f t he  full s can re sul t.Since i ndexesh ave  a d e fa ult sorting order,  w h e nraw tabl es dat a sdo n 't, theex tra cted d ata u sing th e indexis the r ef or e appea ri ng inadif fer ent o r derthan i f it wer e fro m  a full tables can.
In yourc as e th e  4th  ro w is indeed  the 4thonew he n y o u are  usin gt he primary key because  i nterna lly m ysql (oracle,  sql serve r . . .) organ ized it this way to se ek th e data fas t er.
Plea se no te thatby chance , you migh t h ave  ob tai n e dthe same resu l t  inbo th quer ies , justbec aus e t hede fault sel ected re su lt  o rd eris in d eed notpr ove ntobe re l ated t o the  ins er te d  or der.
At la s t , le tme  war n y ou  that  ify ouplanned  to add a n i n dexwi th  a spec ific order in  m ysql (such  a s d escrib e d  here) s o the rows are retrieve d  in, le t s ay, t he D ESC order , y ou cou ldn ot doit sin ce it  i s n o t  an a l l ow edfe ature yeti n  my sql:
A n in dex_col _name specificatio n  ca n end with AS C o r DE S C .The s e ke yw o rds a re permitted fo r future e xt e ns ions for s p eci fy ing asc ending  ord escendi ng indexvalue sto ra ge.C u rre ntly, they  are par sed but
ignor e d;  inde x v aluesar e a lways  store d  in  asce ndingor der.
A:

P ri mary key s are returned in sorte d orde r bydef ault
That s w h y y ou are ge ttin g differen t o utp ut fo r b o th qu erie s .You can c heck with anot h er  ex a m pl e as well:h e r e i s the  ex a mple
 Q:
Why the Coriolis force cannot b e av e cto r i n  the  u sual sense?

W hyth e Coriolis  f orce cannot  be a ve ct o r inthe us ual se nse?

A : 
T h e Cori olis  fo rce on amas sp oint wi th  m a ss $m$   an dveloci ty $\v e c v$ i n a
ORDER BY_myrow desc
LIMIT_1;

I get output as_
+++++++++++++
myid +_myrow
+++++++++++++
A004_+ 4
+++++++++++++

The_difference_between two table_is that in_second table I have_myID as PRIMARY_KEY.
You_can view above data/ result at www.sqlfiddle.com.
My Question is
Why I am getting two different_results_when query_is_same?
NOTE_: This question is bit_related to my old question_Getting last_record from mysql, where I almost got the_answer_and Yak informed_me that the order of rows are not guaranteed._:(

A:

This is because when the selected_fieldset is totally_included_into_a given index fieldset,_this index is used to retrieve_the data instead of the fullscan_result.
Since indexes have a default sorting order,_when raw tables datas don't, the_extracted data using the index_is therefore_appearing in a different order_than if it_were from_a full table_scan.
In your case the 4th row_is indeed the_4th one when you are using_the_primary key because_internally_mysql_(oracle, sql_server...) organized it_this_way to_seek_the data faster.
Please note that by_chance,_you might have obtained the same result_in both queries, just_because_the default selected result_order is indeed not proven_to be related to the inserted_order.
At last,_let me_warn you that if you planned to add an index with_a specific order in mysql (such_as described here) so_the rows_are_retrieved in, let_say,_the DESC_order, you could not do it since_it is_not an allowed feature yet in_mysql:

An index_col_name specification can_end_with ASC or DESC. These
 _keywords are permitted for future extensions_for specifying ascending
  or_descending_index_value storage. Currently, they are_parsed but
  ignored; index values_are always stored_in ascending order.

A:

Primary keys are returned in_sorted_order by default
Thats why you are_getting_different output for both queries.
You can_check_with_another example as well: here_is the example

 Q:

Why the Coriolis_force cannot be a vector in the usual sense?

Why_the Coriolis force_cannot be a vector in_the_usual_sense?

A:

The Coriolis force on a mass point with mass $m$_ and_velocity $\vec v$_in a