將組中的列更新為最小值

Question

我有這樣的數據庫

 uniqueid |     name    | newid | sirname
----------+-------------+-------+---------
     A1   |     Adam    |  NULL |  Danny 
     A2   |  Adam (Lee) |  NULL |  Danny 
     A5   |  Adam (Koh) |  NULL |  Danny
     B4   |     Bruce   |  NULL |    CK
     B6   |  Bruce (Lee)|  NULL |    CK 

我如何將所有的newid 從group by sirname更新為min(unique id)

我想要的結果：

 uniqueid |     name    | newid | sirname
----------+-------------+-------+---------
    A1    |     Adam    |   A1  |  Danny
    A2    |  Adam (Lee) |   A1  |  Danny
    A5    |  Adam (Koh) |   A1  |  Danny
    B4    |     Bruce   |   B4  |   CK
    B6    | Bruce (Lee) |   B4  |   CK

Answer 1

嘗試這個：

UPDATE table a 
SET    new_id = (SELECT MIN(unique_id) 
                 FROM   table b 
                 WHERE  b.sirname = a.sirname)

Answer 2

試試這個UPDATE JOIN

UPDATE
    (
        SELECT sirname,MIN(uniqueid) min_uniqueid
        FROM mytable GROUP BY sirname
    ) A
    INNER JOIN mytable B
    USING (sirname)
SET
    B.newid = A.min_uniqueid
;

為了使該查詢非常快速地工作，請確保您在sirname和uniqueid上具有復合索引。

如果沒有這樣的索引，請事先運行：

ALTER TABLE mytable ADD INDEX sirname_uniqueid_ndx (sirname,uniqueid);

試試看 ！！！

Answer 3

如果BD。無法使用，請嘗試：

Update tableName As a 
  Set newid = 
    (Select uniqueid 
      From tableName As b 
      Where b.sirname = a.sirname 
      Order By uniqueid 
      Limit 1)