mysql - 当所选列中没有值时抛出异常(存储过程)

Question

DROP PROCEDURE IF EXISTS raise;

CREATE PROCEDURE raise(@uld int)
DECLARE EXIT HANDLER FOR SQLEXCEPTION
BEGIN 
    SET @uld = (select ULD_ID from doctor_personal_details)
    IF(@uld = NULL) THEN
        SET MESSAGE_TEXT = ' error occurred';
END;

我在 doctor_personal_details 中有列 ULD_ID，当 ULD_ID 中没有数据时，我需要显示错误消息。

Answer 1

您需要做的是检查是否存在提供的uld记录，如果没有则返回SIGNAL错误，例如:

BEGIN

DECLARE CNT INT;

SELECT COUNT(*) INTO CNT
FROM doctor_personal_details
WHERE ULD_ID = uld;

IF(C = 0) THEN 
  SIGNAL SQLSTATE '45000'
  SET MESSAGE_TEXT = 'No records exist with given uid';
ELSE
  SELECT 'Success' AS message;
END IF;

END