标签：
flow control
the if statement
syntax :
IF condition1 THEN
action1;
[ELsIF condition2 THEN
action2;
[ELSE
action3;]
END IF;
eg :
IF condition THEN
SQL or PL-SQL Commands;
ELSE
SQL or PL-SQL Statements;
END IF;
eg :
DECLARE
l_x NUMBER := 10;
l_y NUMBER := 20;
BEGIN
IF l_x > l_y THEN
DBMS_OUTPUT.put_line(‘ X is bigger than y‘);
ELSIF
DBMS_OUTPUT.put_line(‘
eg :
v_Number1 number(10) := 12;
v_Number2 number(10) := &v_Number2;
eg :add two numbers
DECLARE
--v_Number1 number(10) := 10;
v_Number1 number(10) := &v_Number1;
--v_Number2 number(10) := 30;
v_Number2 number(10) := &v_Number2;
v_result number(10);
BEGIN
v_result := v_Number1 + v_Number2;
DBMS_OUTPUT.put_line(‘Total : ‘ || v_result);
END;
simple loop
a loop is a section of code that needs to be executed a number of times.
syntax :
LOOP
statements..
EXIT WHEN variable condition;
END LOOP;
eg : to display 1 to 10
DECLARE
V1 number := 0;
BEGIN
LOOP
V1 := V1 + 1;
DBMS_OUTPUT.put_line(‘The number is :‘ || V1);
EXIT WHEN V1 > 10;
END loop;
END;
IF condition to check
EXIT;
END IF;
the for loop
no need to declare variable in for loop
check the condition in the beginning
no need to increase the value of the variable
eg :
FOR i in 1..10
LOOP
-- SQL Commands
-- if condition
-- exit when i = 6;
-- if i > 6 then
exit;
END if;
DBMS_OUTPUT.put_line(i);
END LOOP;
for i in reverse 1..10 (from 10 to 1.)
&Start_Num
&End_Num
for in in reverse Start_Num..End_Num
the while loop
a while loop will continue as long as the condition is true.
syntax :
while condition
loop
statements
end loop;
note :
condition check at the beginning
break the loop
increase or decrease the value of a variable
declare the variable
eg :
WHILE l_x <= 100
LOOP
l_x := l_x +10;
END LOOP;
simple loop :
loop
exit when condition true
end loop;
while loop :
while condition
loop
end loop;
labeling loop
you can give loops a label by prefixing the loop with th following :
<< label_name >>
eg :
<<my_loop>>
while l_contimue
eg : in nested loops
<<my_while>>
while i < 10
loop
<<my_for>>
for i in 1..10
loop
if ...
exit my_while; -- jump the outer while loop.
else
exit my_for; -- jump the inner for loop.
end loop;
end loop;
eg :
<<outer>>
while l_continue
loop
<<inner>>
for count in 20..29
loop
l_total := count + l_x;
exit outer when l_total > l_overflow;
end loop inner;
l_continue := l_max > l_total;
end loop ounter;
you can label a block
eg :
<<block1>>
declare
l_x n
the goto statement
to directly jump to a particular section of code. goto is unconditional and final, there is no return,
eg :
declare
l_x NUMBER := 30;
l_y NUMBER :=20;
BEGIN
IF l_x > l_y THEN
GOTO skip_calc;
END IF;
l_x := l_y;
END;
NESTED BLOCKS PL/SQL
labels
labelname.bariablename(from the outer block, if you want to use variables in the inner block.)
eg :Even Numbers
from 1 to 100, display all even numbers using loop.
simple loop
while loop
for loop
END;
while loop :
DECLARE
V1 NUMBER(3) := 0;
BEGIN
WHILE V1 <= 100
LOOP
V1 := V1 + 2
-- or method 2
-- if MOD(V1,2) = 0 THEN
-- DBMS_OUTPUT.put_line(V1);
DBMS_OUTPUT.put_line(V1);
END LOOP;
END;
MOD(V1, 2) = 0 THEN (remaining)
eg :
LOOP
V1 := V1 + 2;
DBMS_OUTPUT.put_line(V1);
EXIT WHEN V1 >= 100;
END LOOP;
eg :
LOOP
IF MOD(V1,2) = 0 THEN
END IF;
END LOOP;
eg : sum of numbers from 1 to 100(using the simple or while or for loop)
DECLARE
V1 NUMBER(10) := 0;
SUM NUMBER(10) := 0;
BEGIN
WHILE V1 <= 100
LOOP
V1 := V1 + 1;
SUM := SUM + V1;
END LOOP;
DBMS_OUTPUT.put_line(SUM);
END;
eg :
DECLARE
Sum1 number(3) := 0;
Num1 number(3) :set = 0;
BEGIN
while Num1 <= 100
loop
Sum1 := Sum1 + Num1;
Num := Num1 + 1;
END loop;
DBMS_OUTPUT.put_line(Sum1);
END;
set serveroutput on
eg : total of odd (1,3,5) numbers from 1 to 100
eg : total of even (2,4,6) numbers from 1 to 100
DECLARE
V1 NUMBER(10) := -1;
total NUMBER(10) := 0;
BEGIN
WHILE V1 <100
LOOP
V1 := V1 + 2;
total := total + V1;
END LOOP;
END;
DECLARE
V1 NUMBER(10) := 0;
total NUMBER(10) := 0;
BEGIN
WHILE V1 <100
LOOP
V1 := V1 + 2;
total := total + V1;
END LOOP;
END;
select MOD(123, 10) from dual; --3
select TRUNC(123/10) from dual; --12
eg : 12345 print 1+2+3+4+5
DECLARE
V1 NUMBER(10) := &V1;
total NUMBER(10) := 0;
remaining NUMBER(10) := 0;
BEGIN
WHILE V1 != 0
LOOP
remaining := MOD(V1, 10);
total := remaining + tota;‘
V1 := TRUNC (V1/10);
END LOOP;
DBMS_OUTPUT.put_line(total);
END;
sum up:
if,elsif, else, end if
loop end loop
while loop
for loop
simple loop
%rowtype
&variable
declare
emp_no number(5) := &emp_no;
employee emp%rowtype;
begin
select * into employee from emp where empno=emp_no;
DBMS_OUTPUT.put_line(‘Employee Number : ‘ || employee.EMPNO);
DBMS_OUTPUT.put_line(‘Employee Number : ‘ || employee.ENAME);
DBMS_OUTPUT.put_line(‘Employee Number : ‘ || employee.JOB);
DBMS_OUTPUT.put_line(‘Employee Number : ‘ || employee.MGR);
DBMS_OUTPUT.put_line(‘Employee Number : ‘ || employee.HIREDATE);
DBMS_OUTPUT.put_line(‘Employee Number : ‘ || employee.SAL);
DBMS_OUTPUT.put_line(‘Employee Number : ‘ || employee.COMM);
DBMS_OUTPUT.put_line(‘Employee Number : ‘ || employee.DEPTNO);
exception
when NO_DATA_FOUND then
DBMS_OUTPUT.put_line(‘EMP does not exist‘);
when OTHERS then
end;
eg : find the largest number from three numbers
eg : write a program to reverse the number (eg : user &input 5678, you output 8765)
DECLARE
NUM NUMBER(10) := &NUM;
REV NUMBER(10) := 0;
REMAIN NUMBER(10) := 0;
BEGIN
WHILE NUM != 0
LOOP
REMAIN := MOD(NUM, 10);
NUM := TRUNC(NUM/10);
REV := REMAIN
END;
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原文地址：http://www.cnblogs.com/jilili/p/4345791.html
