PL/SQL - WHILE LOOP Statement

PL/SQL - WHILE LOOP Statement

A WHILE LOOP statement in PL/SQL programming language repeatedly executes a target statement as long as a given condition is true.
Syntax

WHILE condition LOOP 
   sequence_of_statements 
END LOOP; 

Example Program Display 1-10 numbers

DECLARE 
   a number(2) := 1; 
BEGIN 
   WHILE a <= 10 LOOP 
      dbms_output.put_line('value of a: ' || a); 
      a := a + 1; 
   END LOOP; 
END; 
/

When the above code is executed at the SQL prompt, it produces the following result −
value of a: 1
value of a: 2
value of a: 3
value of a: 4
value of a: 5
value of a: 6
value of a: 7
value of a: 8
value of a: 9

Example Program Display 10-1 numbers

DECLARE 
   a number(2) := 10; 
BEGIN 
   WHILE a >= 1 LOOP 
      dbms_output.put_line('value of a: ' || a); 
      a := a - 1; 
   END LOOP; 
END; 
/

When the above code is executed at the SQL prompt, it produces the following result −

value of a: 10
value of a: 9
value of a: 8
value of a: 7
value of a: 6
value of a: 5
value of a: 4
value of a: 3
value of a: 2
value of a: 1

Nested While Loop

One while loop with in another while

while(condition) loop

	while(condition) loop
	...
	..
	end loop;
..
..
end loop;

Program -1

***
***
***
***
***
***

declare
r int;
c int; 
begin
r:=1;
while(r<=6) loop
	c:=1;
	while(c<=3) loop
	dbms_output.put('*');
	c:=c+1;	
	end loop;

dbms_output.put_line('');
r:=r+1;

end loop;

end;
/

Program -2

*
**
***
****
*****
******



declare
r int;
c int; 
begin
r:=1;
while(r<=6) loop
	c:=1;
	while(c<=r) loop
	dbms_output.put('*');
	c:=c+1;	
	end loop;

dbms_output.put_line('');
r:=r+1;

end loop;

end;
/

Program -3

******
*****
****
***
**
*

declare
r int;
c int; 
begin
r:=1;
while(r<=6) loop
	c:=6;
	while(c>=r) loop
	dbms_output.put('*');
	c:=c-1;	
	end loop;

dbms_output.put_line('');
r:=r+1;

end loop;

end;
/

Program -4

*******
*     *
*     *
*     *
*     *
*     *
*******

declare
r int;
c int; 
begin
r:=1;
while(r<=7) loop
	c:=7;
	while(c>=1) loop
	if(r=1 or c=1 or r=7 or c=7) then
	dbms_output.put('*');
	else
	dbms_output.put(' ');
	end if;
	c:=c-1;	
	end loop;

dbms_output.put_line('');
r:=r+1;

end loop;

end;
/

Program -5

   *   
   *   
   *   
*******
   *   
   *   
   *  

Program -6

declare
r int;
c int; 
begin
r:=1;
while(r<=7) loop
	c:=7;
	while(c>=1) loop
	if(r=4 or c=4 ) then
	dbms_output.put('*');
	else
	dbms_output.put(' ');
	end if;
	c:=c-1;	
	end loop;

dbms_output.put_line('');
r:=r+1;

end loop;

end;
/

Program -7

      *
     **
    ***
   ****
  *****
 ******
*******
declare
r int;
c int; 
begin
r:=1;
while(r<=7) loop
	c:=7;
	while(c>=1) loop
	if(r>=c ) then
	dbms_output.put('*');
	else
	dbms_output.put(' ');
	end if;
	c:=c-1;	
	end loop;

dbms_output.put_line('');
r:=r+1;

end loop;

end;
/