PL/SQL嵌套IF-THEN-ELSE語句

PL/SQL編程嵌套if-else語句，可以使用一個IF或ELSE IF語句中的另一個IF或ELSE IF語句。

語法:

IF( boolean_expression 1)THEN -- executes when the boolean expression 1 is true IF(boolean_expression 2) THEN -- executes when the boolean expression 2 is true
sequence-of-statements; END IF; ELSE -- executes when the boolean expression 1 is not true else-statements; END IF;

示例:

DECLARE a number(3) := 100; b number(3) := 200; BEGIN -- check the boolean condition IF( a = 100 ) THEN -- if condition is true then check the following IF( b = 200 ) THEN -- if condition is true then print the following
dbms_output.put_line('Value of a is 100 and b is 200' ); END IF; END IF; dbms_output.put_line('Exact value of a is : ' || a ); dbms_output.put_line('Exact value of b is : ' || b ); END; /

當上述代碼在SQL提示符執行時，它產生了以下結果：

Value of a is 100 and b is 200
Exact value of a is : 100
Exact value of b is : 200

PL/SQL procedure successfully completed.