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我正在尝试path使用来自同一表的数据更新表中的 hash 和 parType 列。我可以从 SO 上的答案中获取以下 sql，但更新似乎让我失望了。

我在这里尝试做的是更新 hash = 0 和 parType = 0 的所有行，其中 hash = 相同的行 id 和 parType = 该行的父 id 的类型值。

如果你能看到我想要的结果，你就明白了。

你能帮我吗？别管我的sql。

Sql

update path t join(
select t1.id, t1.type, t2.parent from path t1, path t2 where t1.parent = t2.id;
) as p on p.id=t.id set hash = t1.id and parType = t1.type;

更新前

"id"    "type"  "parent"    "hash"  "parType"
"1"     "0"     "0"         "0"     "0"
"2"     "2"     "1"         "0"     "0"
"3"     "3"     "2"         "0"     "0"
"4"     "4"     "3"         "0"     "0"

期望的结果

"id"    "type"  "parent"    "hash"  "parType" //parType = the type of the parent
"1"     "0"     "0"         "1"     "0"
"2"     "2"     "1"         "2"     "0"
"3"     "3"     "2"         "3"     "2" -> This is value from the parents type
"4"     "4"     "3"         "4"     "3"

编辑 - 这行得通，但我仍然不确定这是否是正确的方法

update path a join(
select t1.id as hash, t2.type as parType from path t1 inner join path t2 on t1.parent = t2.id
) b on a.id=b.hash set a.hash = b.hash , a.parType = b.parType;
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3 回答 3

1

像这样的东西？

UPDATE table1 t LEFT JOIN
(SELECT t1.id,t1.type FROM table1 t1 INNER JOIN table1 t2 ON t1.id>t2.id GROUP BY t1.id) as p 
ON p.id+1=t.id SET t.hash=t.id,t.parType=ifnull(p.type,0)

SQL小提琴

于 2013-10-20T15:44:26.550 回答
0

请试试这个

update path t join(
select t1.id, t2.type, t2.parent from path t1, path t2 where t1.parent = t2.id;
              ^^
) as p on p.id=t.id set hash = t1.id and parType = t2.type;
                                                   ^^

我已将内部连接从t1.typetot2.type和ON条件从parType = t1.typetoparType = t2.type

于 2013-10-20T15:44:16.313 回答
0

尝试这个

update t set 
   hash = t.id,
   partype = p.type
from path t 
   left join path p
      on p.id = t.parent
where hash = 0 
   and parType = 0
于 2013-10-20T15:46:20.760 回答