Question

当我调用以下PL / SQL函数时，出现错误“找不到数据”

FUNCTION get_Deployment_Status(i_deploymentId deployments.pk%type)
RETURN VARCHAR2
IS
    o_status varchar2(30);
BEGIN
    SELECT distinct Status
    into   o_status
    FROM   deployments
    WHERE  Pk=i_deploymentId; 

    return o_status;
END;

我传递了Deploymentid（这是一个数字），我希望状态以字符串形式返回。有更好的方法吗？为什么我会收到该错误？

Answer 1

看看以下选项。阅读代码中的注释。

选项1：

FUNCTION get_deployment_status (i_deploymentid deployments.pk%TYPE)
   RETURN VARCHAR2
IS
   o_status  VARCHAR2 (30);
BEGIN
   -- This option will return O_STATUS if something is found. If not, NO_DATA_FOUND
   -- EXCEPTION section will handle it.
   -- You most probably don't need DISTINCT nor TOO_MANY_ROWS handling as it appears that
   -- you're dealing with a primary key column; are you? If not, well, you'll have to 
   -- handle that option as well.
   SELECT status
     INTO o_status
     FROM deployments
    WHERE pk = i_deploymentid;

   RETURN o_status;
EXCEPTION
   WHEN NO_DATA_FOUND
   THEN
      RETURN NULL;
END;

选项2：

FUNCTION get_deployment_status (i_deploymentid deployments.pk%TYPE)
   RETURN VARCHAR2
IS
   o_status  VARCHAR2 (30);
BEGIN
   -- This option will return NULL into O_STATUS if there's nothing found.
   -- It won't raise the NO_DATA_FOUND exception. 
   -- Just like above, if it is a primary key column involved in the WHERE 
   -- clause, you shouldn't care whether MAX will return correct value or not,
   -- because - if it exists - it will be the only value.
   SELECT MAX (status)
     INTO o_status
     FROM deployments
    WHERE pk = i_deploymentid;

   RETURN o_status;
END;

PL / SQL“未找到数据”

1 个答案: