case 语句匹配顺序

来源：互联网发布：sql server 分组编辑：程序博客网时间：2024/06/06 16:55
<pre name="code" class="sql">mysql> select * from ClientLoginDevice;+--------------+| machineModel |+--------------+| Android01    || Android02    || Android03    || Androidpc    || ios01        || ios02        || ios03        || ios04        || iospc        || pc01         || pc02         |+--------------+11 rows in set (0.00 sec)mysql> SELECT machineModel,    ->             CASE    ->                 WHEN machineModel LIKE '%Android%' THEN 'Android'    ->                 WHEN machineModel LIKE '%ios%' THEN 'ios'    ->                 WHEN machineModel LIKE '%wechat%' THEN 'wechat'    ->                 ELSE 'pc'    ->             END AS machineModel    ->     FROM ClientLoginDevice    -> GROUP BY machineModel;+--------------+--------------+| machineModel | machineModel |+--------------+--------------+| Android01    | Android      || Android02    | Android      || Android03    | Android      || Androidpc    | Android      || ios01        | ios          || ios02        | ios          || ios03        | ios          || ios04        | ios          || iospc        | ios          || pc01         | pc           || pc02         | pc           |+--------------+--------------+11 rows in set, 1 warning (0.00 sec)可以看到Androidpc 同时匹配Android和pc,但是统计时都算入到Android 类型iospc 也是同样的道理
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