当我在哪里使用date_add不工作时，为什么？

Question

SELECT * 
FROM PATIENT
WHERE PATIENTNUM = (SELECT PATIENTNUM
                     FROM CONSULTATION
                     WHERE CONSULTATIONDATE =  
                     (SELECT DATE_ADD(curdate(), INTERVAL 1 DAY) AS DAYTOM); 

这不起作用。

但是当我只插入这个

时

SELECT DATE_ADD(curdate(), INTERVAL 1 DAY) AS DAYTOM

它的工作......

为什么？

Answer 1

我认为正确的方法是

  SELECT * 
  FROM PATIENT
   WHERE PATIENTNUM IN (SELECT PATIENTNUM
                 FROM CONSULTATION
                 WHERE CONSULTATIONDATE IN  (SELECT DATE_ADD(curdate(), INTERVAL 1 DAY)             AS   DAYTOM)); 

Answer 2

你错过了一个支架？

SELECT * 
FROM PATIENT
WHERE PATIENTNUM = (SELECT PATIENTNUM
                     FROM CONSULTATION
                     WHERE CONSULTATIONDATE =  (SELECT DATE_ADD(curdate(), INTERVAL 1 DAY) AS DAYTOM));