在PL/SQL编程中嵌套IF-ELSE语句总是合法的，也就是说可以在一个IF或ELSE IF语句中使用另一个IF或ELSE IF语句。
语法
PL/SQL中嵌套IF-ELSE语句的语法是 -
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;
实例
请参考以下示例代码 -
SET SERVEROUTPUT ON SIZE 1000000;
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;
/
当上述代码在SQL提示符下执行时，它会产生以下结果 -
