在PL/SQL编程中,将 IF-ELSE 语句嵌套通常是合法的,这意味着您可以在其中使用一个 IF 或 ELSE IF 语句另一个 IF 或 ELSE IF 语句。
嵌套 IF-THEN-ELSE - 语法
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;
嵌套 IF-THEN-ELSE - 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; /
当以上代码在SQL提示符下执行时,将产生以下输出-
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.