Row Generators in Oracle

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Category: 
SQL : select  level from dual connect by level <= 100 ;

this generates 100 rows of numbers 1..100. But row generators aren't limited to numbers. 
By using date arithmetic, you can generate dates:
select  date '2015-01-01' + level -1 as gendate  from    dual 
connect by date '2015-01-01' + level -1 < date '2015-02-01' ; 
01-01-2015 
02-01-2015 
.
.
.
30-01-2015
31-01-2015


31 rows selected.






Or by using ASCII codes, you can generate characters:


select chr(65 + level - 1) as letter  from dual  connect by level <= 26; 


 LETT 


 ---- 





 


  A
 



  B
 



  C
 



  D
 



  E
 



  F
 



  G
 



  H
 



  I
 



  J
 



  K
 



  L
 



  M
 



  N
 



  O
 



  P
 



  Q
 



  R
 



  S
 



  T
 



  U
 



  V
 



  W
 



  X
 



  Y
 



  Z
 




26 rows selected.