问题描述

我试图了解如何使用不同的值更新多行，但我不明白.解决方案无处不在，但在我看来很难理解.

I am trying to understand how to UPDATE multiple rows with different values and I just don't get it. The solution is everywhere but to me it looks difficult to understand.

例如，三个更新为 1 个查询:

For instance, three updates into 1 query:

UPDATE table_users
SET cod_user = '622057'
    , date = '12082014'
WHERE user_rol = 'student'
    AND cod_office = '17389551'; 

UPDATE table_users
SET cod_user = '2913659'
    , date = '12082014'
WHERE user_rol = 'assistant'
    AND cod_office = '17389551'; 

UPDATE table_users
SET cod_user = '6160230'
    , date = '12082014'
WHERE user_rol = 'admin'
    AND cod_office = '17389551'; 

我 阅读 一个例子，但我真的不明白如何进行查询.即:

I read an example, but I really don't understand how to make the query. i.e:

UPDATE table_to_update
SET cod_user= IF(cod_office = '17389551','622057','2913659','6160230')
    ,date = IF(cod_office = '17389551','12082014')
WHERE ?? IN (??) ;

如果 WHERE 和 IF 条件中有多个条件，我不完全清楚如何进行查询..有什么想法吗?

I'm not entirely clear how to do the query if there are multiple condition in the WHERE and in the IF condition..any ideas?

推荐答案

你可以这样做:

UPDATE table_users
    SET cod_user = (case when user_role = 'student' then '622057'
                         when user_role = 'assistant' then '2913659'
                         when user_role = 'admin' then '6160230'
                    end),
        date = '12082014'
    WHERE user_role in ('student', 'assistant', 'admin') AND
          cod_office = '17389551';

我不明白你的日期格式.日期应使用本机日期和时间类型存储在数据库中.

I don't understand your date format. Dates should be stored in the database using native date and time types.

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