Question

我正在开展一个项目，我需要在查询中更新2个表。

我这样做

UPDATE ward_beds a, ipd_patient_list b 
SET 
a.occupation_status = 'empty', 
b.patient_status = 'Discharged' 
WHERE 
a.ward_id = b.ward_id AND b.patient_id = '4' 
AND 
b.appointment_id = '6' AND b.ward_id = '1'

到目前为止它正在运行，现在我想更新此

b.patient_status = 'Discharged'

在所有匹配行中的最后一行。我试着把这个

ORDER BY b.row_id DESC LIMIT 1

但它显示

#1221 - Incorrect usage of UPDATE and ORDER BY

错误。我该怎么办？

Answer 1

您不能在此类更新中使用限制但你可以使用子查询搜索正确的id并加入其他表

  UPDATE ward_beds a
  INNER JOIN (
    select  ward_id, max(row_id)  last_id 
    from ipd_patient_list
    group by ward_id
  ) t on t.ward_id = a.ward_id
  INNER JOIN ipd_patient_list b  ON a.ward_id = b.ward_id
        AND b.patient_id = '4' 
          AND b.appointment_id = '6' 
            AND b.ward_id = '1' 
              AND b.row_id = t.last_id
SET a.occupation_status = 'empty', 
    b.patient_status = 'Discharged'

更新多个表中的行和

1 个答案: