根据另一个表上的数据更新一个表

Question

任何人都可以用php代码来帮助我解决这个问题，我是php的新手。我有2个名为“ registration”表和“ first_allotement”表的表

“注册”表：

Altno | pid | appno | name | college1 | college2 | college3 | college4  | college5 | college6 | college7 | college8 | college9 | college10

“第一批”表：

Altno | appno | name | college | curdate | markdate | total | pdf

比较“ first_allotement”表中的“ college”字段和“ registration”表字段“ college1”，“ college2” .....“ college10”（如果值与任何字段匹配），然后更新“ registration”表中的相应字段具有空值..所以请给我一个更好的PHP代码来解决它

Answer 1

使用更新联接：

update table registration join first_allotement
on registration .appno =first_allotement.appno and first_allotement.college=(registration.college1 or registration.college1 or registration.college2 or registration.college3 or registration.college4 or registration.college5 or registration.college6 or registration.college7 or registration.college8 or registration.college9 or registration.college10)
set registration.college1=null, registration.college2=null, registration.college3=null ....