[英]MySQL Query - Join Subquery
What I have 我有的
I have multiple Tables like this: 我有多个这样的表:
- tbl_hw_inventar (hw_id, hostname, hw_typ_idfs, hw_created_user_idfs, etc...) tbl_hw_inventar(hw_id,主机名,hw_typ_idfs,hw_created_user_idfs等)
- tbl_hw_typ (hw_typ_id, hw_typ_title, etc...) tbl_hw_typ(hw_typ_id,hw_typ_title等)
- tbl_user (user_id,username, etc...) tbl_user(用户ID,用户名等)
- tbl_hw_edited (hw_edited_id, hw_edited_client_idfs, hw_edited_date, hw_edited_user_idfs) tbl_hw_edited(hw_edited_id,hw_edited_client_idfs,hw_edited_date,hw_edited_user_idfs)
What I need 我需要的
I want output a table with the following information: 我要输出包含以下信息的表:
hw_id | Hostname | created | last edited
12315 | client-01 | 2015-05-06 15:31:06 (username) | 2015-07-02 09:46:17 (username) |
The problem 问题
As you can see, I can get information like the hw_typ with a foreign key and a inner join to the " tbl_hw_typ
". 如您所见,我可以获得带有外键和对“ tbl_hw_typ
”的内部 tbl_hw_typ
之类的信息。 The same for information with " hw_created_user_idfs
" and a inner join to get the username for the userid . 对于带有“ hw_created_user_idfs
”和内部hw_created_user_idfs
以获取用户 ID 用户名的信息也是如此。
But how can I get the last edited , datetime and the username ? 但是,如何获取最后编辑的 日期时间和用户名 ?
In my table " tbl_hw_edited
" i have entries like this: 在我的表“ tbl_hw_edited
”中,我有这样的条目:
row id | hw_id | datetime | user_id
The code 编码
My SQL query looks like this so far: 到目前为止,我的SQL查询如下所示:
SELECT `tbl_hw_inventar`.*, `tbl_hw_typ`.`hw_typ_title`, `tbl_user`.`username`, `tbl_hw_edited`.`hw_edited_id`
FROM `tbl_hw_inventar`
INNER JOIN `tbl_hw_typ`
ON `tbl_hw_inventar`.`hw_typ_idfs` = `tbl_hw_typ`.`hw_typ_id`
INNER JOIN `tbl_user`
on `tbl_hw_inventar`.`hw_create_user_idfs` = `tbl_user`.`id`
JOIN (
SELECT MAX(`tbl_hw_edited`.`hw_edited_id`), `tbl_hw_edited`.`hw_edited_client_idfs`
FROM `tbl_hw_edited`
) `tbl_hw_edited` ON `tbl_hw_inventar`.`hw_id` = `tbl_hw_edited`.`hw_edited_client_idfs`
ORDER BY `tbl_hw_inventar`.`hw_id` ASC
So how can I export the information? 那么如何导出信息? It looks like I have to make a subquery in my query. 看来我必须在查询中进行子查询。 But I failed with every try. 但是我每次尝试都失败了。
Thanks for you help 谢谢你的帮助
EDIT 编辑
As proposed I'm providing more information (table data) for each table: 按照提议,我将为每个表提供更多信息(表数据):
-tbl_hw_inventar-
| hw_id | hw_hostname | hw_create_date | hw_create_user_idfs |
| 1 | client-01 | 2015-03-06 11:57:42 | 1 |
| 2 | client-02 | 2015-09-21 21:17:00 | 3 |
-tbl_hw_edited-
| hw_edited_id | hw_edited_client_idfs | hw_edited_date | hw_edited_user_idfs |
| 1 | 1 | 2015-09-24 17:30:22 | 1 |
| 2 | 2 | 2015-09-24 16:33:22 | 2 |
| 3 | 1 | 2015-09-24 23:30:22 | 2 |
| 4 | 2 | 2015-09-24 20:30:22 | 3 |
-tbl_user-
| id | username |
| 1 | ismaelw |
| 2 | skalb |
| 3 | yrumpel |
So as a final result I need an output like this: 因此,作为最终结果,我需要这样的输出:
| hw_id | hostname | created | edited |
| 1 | client-01 | 2015-03-06 11:57:42 (ismaelw) | 2015-09-24 23:30:22 (skalb) |
If I have interpreted your tables correctly, you need to find the max(edit date) for each hw_edited_client_idfs (which joins to hw_id) 如果我正确地解释了您的表,则需要为每个hw_edited_client_idfs(与hw_id连接)找到最大(编辑日期)
SELECT
hw_edited_client_idfs
, MAX(hw_edited_date) AS last_edit_dt
FROM tbl_hw_edited
GROUP BY hw_edited_client_idfs
With that result you may join it back to the source table, to discover which user is associated to the max(edit date) 通过该结果,您可以将其重新连接到源表,以发现与最大(编辑日期)关联的用户
SELECT
het.*
FROM tbl_hw_edited AS het
INNER JOIN (
SELECT
hw_edited_client_idfs
, MAX(hw_edited_date) AS last_edit_dt
FROM tbl_hw_edited
GROUP BY hw_edited_client_idfs
) AS mx ON het.hw_edited_client_idfs = mx.hw_edited_client_idfs
AND het.hw_edited_date = mx.last_edit_dt
Then this result used like so: 然后,该结果使用如下:
SELECT
i.hw_id
, i.hw_hostname
, uc.username created_by
, he.hw_edited_date last_edit_date
, ue.username last_edit_by
FROM tbl_hw_inventar AS i
INNER JOIN tbl_user AS uc ON i.hw_create_user_idfs = uc.id
LEFT OUTER JOIN (
SELECT
het.*
FROM tbl_hw_edited AS het
INNER JOIN (
SELECT
hw_edited_client_idfs
, MAX(hw_edited_date) AS last_edit_dt
FROM tbl_hw_edited
GROUP BY hw_edited_client_idfs
) AS mx ON het.hw_edited_client_idfs = mx.hw_edited_client_idfs
AND het.hw_edited_date = mx.last_edit_dt
) AS he ON i.hw_id = he.hw_edited_client_idfs
LEFT OUTER JOIN tbl_user AS ue ON he.hw_edited_user_idfs = ue.id
which produces this result: 产生以下结果:
| hw_id | hw_hostname | username | hw_edited_date | username |
|-------|-------------|----------|-----------------------------|----------|
| 1 | client-01 | ismaelw | September, 24 2015 23:30:22 | skalb |
| 2 | client-02 | yrumpel | September, 24 2015 20:30:22 | yrumpel |
see this sqlfiddle 看到这个sqlfiddle
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