如何混合列數據

Question

我有一張桌子table_1

 id     contact_id
 1         500
 5         89
 8         35
 15        458
 ...       ...
 555       38

如何混合contact_id和table_1結果

id     contact_id
 1         35
 5         458
 8         35
 15        89
 ...       ...
 555       45

Answer 1

您可以使用變量或row_number() （在MySQL 8+中）隨機分配聯系人ID：

select t1.id, tt1.contact_id
from (select t1.*, row_number() over (order by id) as seqnum
      from table_1 t1
     ) t1 join
     (select t1.*, row_number() over (order by rand()) as seqnum
      from table_1 t1
     ) tt1
     on t1.seqnum = tt1.seqnum;

沒有太多困難（但需要更多鍵入），可以將其轉換為使用早期版本中的變量。

如果要永久地改組值，也可以將其合並到update語句中。

編輯：

我想你要：

update table1 t1 join
       (select t1.id, tt1.contact_id
        from (select t1.*, (@rn1 := @rn1 + 1) as seqnum
              from (select * table_1 order by id) t1 cross join
                   (select @rn1 := 0) params
             ) t1 join
             (select t1.*, (@rn2 := @rn2 + 1) as seqnum
              from (select * from table_1 order by rand()) t1 cross join
                   (select @rn2 := 0) params
             ) tt1
             on t1.seqnum = tt1.seqnum
       ) tt1
       on tt1.id = t1.id
    set t1.contact_id = tt1.contact_id;