PLSQL的控制

--PL/SQL控制流程
--条件控制语句
DECLARE
V_VAR NUMBER(4) := 3;
BEGIN
? IF V_VAR = 1
??? THEN
?? DBMS_OUTPUT.PUT_LINE('V_VAR=' || V_VAR);??
? ELSIF V_VAR = 2
?? THEN
?? DBMS_OUTPUT.PUT_LINE('V_VAR=' || V_VAR);????
? ELSE
?? DBMS_OUTPUT.PUT_LINE('V_VAR=' || V_VAR);
? END IF;
? END;
/

--循环语句
--1.LOOP......END LOOP
DECLARE
V_COUNT BINARY_INTEGER := 1;
BEGIN
? LOOP???
??? DBMS_OUTPUT.PUT_LINE('V_COUNT=' || V_COUNT);
??? V_COUNT := V_COUNT + 1;
??? IF V_COUNT = 10 THEN
????? EXIT;
????? END IF;
??? END LOOP;
??? DBMS_OUTPUT.PUT_LINE('V_COUNT循环后的值是：'||V_COUNT);
??? END;
/

--FOR循环
/*
格式
FOR V_VAR IN (REVERSE) 10 .. 20
? LOOP
?? do something;
?? END LOOP;

*/
DECLARE
V_COUNT BINARY_INTEGER := 1;
BEGIN
? FOR V_COUNT IN 10 .. 20
??? LOOP????
????? DBMS_OUTPUT.PUT_LINE('V_COUNT=' || V_COUNT);
????? IF V_COUNT? = 30 THEN
??????? EXIT;
??????? END IF;
????? END LOOP;
????? END;
/

--WHILE循环
/*
WHILE V_VAR < 20
? LOOP
??? END LOOP;
*/
DECLARE
V_COUNT BINARY_INTEGER := 1;
BEGIN
? WHILE V_COUNT <= 10
??? LOOP
????? V_COUNT := V_COUNT + 1;
????? DBMS_OUTPUT.PUT_LINE('V_COUNT=' || V_COUNT);
????? END LOOP;
????? END;
/

--条件退出LOOP循环
DECLARE
V_VAR NUMBER(4) := 1;
BEGIN
? LOOP
??? V_VAR := V_VAR +2;
??? EXIT WHEN V_VAR > 20;
??? DBMS_OUTPUT.PUT_LINE('V_VAR = ' || V_VAR);
??? END LOOP;
??? END;
/

--条件CONTINUE? LOOP循环
DECLARE
V_VAR NUMBER(4) := 1;
BEGIN
? LOOP
??? V_VAR := V_VAR +2;
??? IF V_VAR < 10 THEN
???? DBMS_OUTPUT.PUT_LINE('HELLO,WORLD;V_VAR = ' || V_VAR);
??? END IF;
??? CONTINUE WHEN V_VAR < 10;
??? EXIT WHEN V_VAR > 20;
??? DBMS_OUTPUT.PUT_LINE('V_VAR = ' || V_VAR);
??? END LOOP;
??? END;
/