不能在 Oracle 9i 中使用“如果存在”语句

Question

我有以下代码：

INSERT INTO Table_Delete (name)
SELECT su_name
FROM   Student_Data
where class = '12'
MINUS
SELECT name
  FROM Students
  WHERE roll_num in (select roll_num from RollNumber
                       where class = '12');
COMMIT;
exit

我需要更新此代码以检查 Table_Delete = Table_2 的内容是否清空Table_delete。我无法通过"如果存在"命令执行此操作。

任何人都可以帮我吗？我正在使用Oracle 9i。

Answer 1

select count(*) into ws_count from x where table_delete = table_2;
if(ws_count = 1) then

这边