Select into 语句用于 null 或多个值

Question

我被困在plsql 中，因为我有一个函数，如果只有值进入选择中，我必须更新一个表..

如果不来，那么不来，如果有多个，则必须更新和删除所有这些值。

在下面的函数中，如果第一次选择 null 值，则不应进行异常处理，应仅更新 CUSTOMER 表并仅从表 3 中删除，如果出现一个或多个值，则对每个值进行全部更新和删除

 create or replace FUNCTION  FUNCTION_NAME (
   from_PARTICIPANT_KEY1   IN NUMBER
)
  RETURN 
IS
   to_participant_key1   NUMBER (11);
BEGIN
   SELECT   to_participant_key
     INTO   to_participant_key1
     FROM   TABLE2
    WHERE   FROM_PARTICIPANT_KEY = from_PARTICIPANT_KEY1;




  UPDATE   CUSTOMERS C
      SET   C.CUSTOMER_STATUS_CD =
               NVL (
                  (SELECT   old_status_cd
                     FROM   TABLE1
                    WHERE   PARTICIPANT_UID = from_PARTICIPANT_KEY1
                            AND participant_cd = 'CUSTOMER'),
                  C.CUSTOMER_STATUS_CD
               )
    WHERE   C.CUSTOMER_UID = from_PARTICIPANT_KEY1;



   UPDATE   subscribers C
      SET   C.STATUS_CD =
               NVL (
                  (SELECT   old_status_cd
                     FROM   TABLE1
                    WHERE   PARTICIPANT_UID = to_participant_key1
                            AND participant_cd = 'SUBSCRIBER'),
                  C.STATUS_CD
               )
    WHERE   C.account_no = to_participant_key1;

   DBMS_OUTPUT.PUT_LINE ('Delete TABLE1 rows');

   DELETE FROM   TABLE3
         WHERE   PARTICIPANT_UID = from_PARTICIPANT_KEY1 AND participant_cd = 'CUSTOMER';

   DELETE FROM   TABLE1
         WHERE   PARTICIPANT_UID = to_PARTICIPANT_KEY1 AND participant_cd = 'SUBSCRIBER';



   COMMIT;



EXCEPTION  -- exception handlers begin
   WHEN NO_DATA_FOUND  THEN  -- handles 'division by zero' error
      dbms_output.put_line('Customer not found ' || from_PARTICIPANT_KEY1);

   WHEN OTHERS THEN  -- handles all other errors
      dbms_output.put_line('Some other kind of error occurred.');


END;

Answer 1

您可以使用BULK COLLECT INTO 并遍历集合。

首先，你必须声明（或使用一些现有的）集合类型并创建该类型的变量：

  TYPE participant_keys is table of number (11); 
  l_participant_keys participant_keys;

然后，您的查询将更改为：

  SELECT to_participant_key
  BULK COLLECT INTO to_participant_key1
  FROM TABLE2
  WHERE FROM_PARTICIPANT_KEY = from_PARTICIPANT_KEY1;

如果查询不会返回任何记录，那么您可以使用COUNT 进行检查：

if l_participant_keys.COUNT = 0 then
 -- update only CUSTOMER table and only delete from table 3
else
  FOR I IN l_participant_keys.FIRST .. l_participant_keys.LAST LOOP
    --use l_participant_keys(i) do all update and delete for each value
  END LOOP;
end if;