Question

我有一张桌子＆＃34; projectdetails＆＃34;其中parent_id是同一表中列project_id的外键..

从下面的记录我只想要那些parent_id行，没有＆＃39; recycle_bin`值为1的行，并且还应该显示creater_id = 7923的记录;

我有这样的记录：

mysql> SELECT *FROM  projectdetails;
+------------+-----------------+-----------+-------------+------------+
| project_id | project_name    | parent_id | recycle_bin | creater_id |
+------------+-----------------+-----------+-------------+------------+
|          0 | -               |         0 |           0 |       7898 |
|        100 | Country         |         0 |           2 |       7923 |
|        101 | animal          |         0 |           1 |       7923 |
|        102 | India           |       100 |           2 |       7923 |
|        103 | pakistan        |       100 |           2 |       7923 |
|        104 | cow             |       101 |           1 |       7923 |
|        105 | elephant        |       101 |           1 |       7923 |
|        109 | black elephent  |       105 |           1 |       7923 |
|        110 | white elephent  |       105 |           2 |       7923 |
|        111 | wild black elep |       109 |           1 |       7923 |
|        112 | simple blak elp |       109 |           1 |       7923 |
|        113 | lion            |       105 |           1 |       7923 |
|        114 | red lion        |       113 |           1 |       7923 |
|        115 | black lion      |       113 |           1 |       7923 |
|        116 | girls           |         0 |           1 |       7923 |
|        117 | good girls      |       116 |           1 |       7923 |
|        118 | funky girls     |       116 |           1 |       7923 | 
+------------+-----------------+-----------+-------------+------------+
7 rows in set (0.00 sec)

预期产出：

+------------+----------------+-----------+-------------+------------+
| project_id | project_name   | parent_id | recycle_bin | creater_id |
+------------+----------------+-----------+-------------+------------+ 
|        100 | Country        |         0 |           2 |       7923 | 
|        110 | white elephent |       105 |           2 |       7923 |
+------------+----------------+-----------+-------------+------------+

注意：这是树结构表，这里每个子id上的用户都可以插入很多其他记录。就像树结构一样。所以请回答与此说明相关的内容。

如果你无法得到我的要求，那么请写评论，我会试着解释你......

更新

所以基本上，当查询读取一行来决定它是否适用于显示时，

第一个查询流程：对国家说。

首先找一行说INDIA，＆amp;然后接下来看看它的parent_id，如果它有parent_id，那么转到那个parent_id（现在这是一个project_id = 100），所以接下来再看看它是否有父项，如果没有，则查看列recycle_bin ..如果1然后显示这个结果或否则忽略。

Answer 1

尝试此查询，

SELECT 
project_id,project_name,parent_id,recycle_bin,creater_id 
FROM projectdetails
WHERE recycle_bin not in (select recycle_bin from projectdetails where recycle_bin = 1 )
AND creater_id = 7923;

否则请尝试@SamD建议，

SELECT 
project_id,project_name,parent_id,recycle_bin,creater_id 
FROM projectdetails
WHERE recycle_bin != 1
AND creater_id = 7923;

Answer 2

根据您的描述和示例输出，您似乎只想查看带有以下内容的记录：

recycle_bin＆gt; 1

父树的最顶层节点。最顶层节点由具有当前节点的parent_id的项目是否与所讨论的creater_id一起确定。

creater_id = 7923 。

因此，要获得这些条件，您需要三个过滤器：

SELECT CURRENT_ROW.PROJECT_ID ,CURRENT_ROW.PROJECT_NAME ,CURRENT_ROW.PARENT_ID ,CURRENT_ROW.RECYCLE_BIN ,CURRENT_ROW.CREATER_ID FROM PROJECTDETAILS CURRENT_ROW WHERE recycle_bin != 1 AND creater_id=7923 /* This will determine if the node is the topmost based on whether it has a parent */ AND NOT EXISTS ( select 1 FROM PROJECTDETAILS PARENT where CURRENT_ROW.parent_id = PARENT.project_id and PARENT.creater_id = CURRENT_ROW.creater_id and PARENT.recycle_bin != 1 );

有关工作示例，请参阅此sqlfiddle：

这可以获得您正在寻找的确切输出。

Answer 3

这样的事情？ FIDDLE以供参考

SELECT project_id,project_name,parent_id,recycle_bin,creater_id
FROM projectdetails AS pd1
JOIN(
    SELECT parent_id FROM projectdetails as pd
    WHERE pd.parent_id > 0 AND pd.recycle_bin > 1
) AS t ON t.parent_id = pd1.project_id

使用新数据.. NEW_FIDDLE

SELECT 
  if(pd1.recycle_bin >1, pd1.project_id, t.project_id) AS project_id,
  if(pd1.recycle_bin >1, pd1.project_name, t.project_name) AS project_name,
  if(pd1.recycle_bin >1, pd1.parent_id, t.parent_id) AS parent_id,
  if(pd1.recycle_bin >1, pd1.recycle_bin, t.recycle_bin) AS recycle_bin,
  if(pd1.recycle_bin >1, pd1.creater_id, t.creater_id) AS creater_id
FROM projectdetails AS pd1
JOIN(
  SELECT * FROM projectdetails AS pd
  WHERE pd.parent_id > 0 
    AND pd.recycle_bin > 1
) AS t ON t.parent_id = pd1.project_id
GROUP BY project_id

不使用IF＆＃39; LAST_FIDDLE

SELECT 
   pd1.project_id,
   pd1.project_name,
   pd1.parent_id,
   pd1.recycle_bin,
   pd1.creater_id
FROM projectdetails AS pd1
WHERE NOT EXISTS(
  SELECT pd.recycle_bin FROM projectdetails as pd
  WHERE pd1.parent_id = pd.project_id 
    AND pd.recycle_bin > 1
) AND pd1.creater_id = 7923 and pd1.recycle_bin > 1
GROUP BY pd1.project_id;

SQL：循环遍历同一个表

3 个答案: