Php 如果学生的出入境状态为“1”，则罚款将增加1；0“；地位

我有两个表，日志和学生日志，我想选择状态为“in”和“out”的学生id，状态为“0”。如果学生id有in和out，则学生中的惩罚计数将增加

日志

如果学生的状态为“0”，则惩罚将增加1。 日志

请帮我谢谢。试试这个

UPDATE student SET penalty_count = (penalty_count + 1) 
WHERE cardcode IN 
(SELECT GROUP_CONCAT(stud_id) FROM log WHERE status_log = 'IN' AND status_log = 'OUT' 
AND status = 0 GROUP BY stud_id)

试着这样做：

UPDATE student 
SET penalty=penalty + 1
WHERE cardcode IN (
  SELECT l1.stud_id FROM log AS l1
  JOIN log AS l2 ON l1.stud_id=l2.stud_id AND l2.status_log = 'out' AND l2.status = 0
  WHERE l1.status_log = 'in' AND l1.status = 0
  GROUP BY l1.stud_id
)

---

这在没有连接说明的情况下也是可能的。您可以将此

键（stud\u id、status、status\u log）

添加到表日志中，以获得更好的性能

update 
 penalty
set
  penalty_count = penalty_count + 1 
where 
 cardcode IN(
   select 
     stud_id
   from 
    log
   where 
    status = 0
   group by 
    stud_id
   having 
    (sum(status_log = 'in') + sum(status_log = 'out')) = 2
   order by 
    null
)

注意，

order by null

用于禁用group by函数的默认排序（解释输出中的filesort），因为更新时不需要对结果进行排序

---

参见演示

在

学生

表中也应该有一个

螺柱id

。螺柱id是cardcode sir

UPDATE student 
SET penalty=penalty + 1
WHERE cardcode IN (
  SELECT l1.stud_id FROM log AS l1
  JOIN log AS l2 ON l1.stud_id=l2.stud_id AND l2.status_log = 'out' AND l2.status = 0
  WHERE l1.status_log = 'in' AND l1.status = 0
  GROUP BY l1.stud_id
)

update 
 penalty
set
  penalty_count = penalty_count + 1 
where 
 cardcode IN(
   select 
     stud_id
   from 
    log
   where 
    status = 0
   group by 
    stud_id
   having 
    (sum(status_log = 'in') + sum(status_log = 'out')) = 2
   order by 
    null
)