postgresql - 使用聚合和最大值
postgresql - using aggregation and max
我有这个table:
abs=# \d import.vw_rpt_certification
Table "import.vw_rpt_certification"
Column | Type | Collation | Nullable | Default
------------------------------+------+-----------+----------+---------
user_id | text | | |
cert_object_id | text | | |
version | text | | |
cert_is_active | text | | |
cert_modify_dt | text | | |
period_type | text | | |
user_cert_status | text | | |
first_period_completion_date | text | | |
period_expiration_date | text | | |
period_due_date | text | | |
user_lo_active | text | | |
user_lo_last_action_dt | text | | |
cert_is_on_hold | text | | |
user_lo_assigned_dt | text | | |
user_lo_last_modified_dt | text | | |
user_lo_status_id | text | | |
user_lo_status | text | | |
user_cert_is_archived | text | | |
is_current_period | text | | |
select * from import.vw_rpt_certification limit 10;
user_id | cert_object_id | version | cert_is_active | cert_modify_dt | period_type | user_cert_status | first_period_completion_date | period_expiration_date | period_due_date | user_lo_active | user_lo_last_action_dt | cert_is_on_hold | user_lo_assigned_dt | user_lo_last_modified_dt | user_lo_status_id | user_lo_status | user_cert_is_archived | is_current_period
---------+--------------------------------------+---------+----------------+--------------------------+------------------+------------------------------------------+------------------------------+------------------------+----------------------+----------------+-------------------------+-----------------+--------------------------+--------------------------+-------------------+----------------+-----------------------+-------------------
109485 | 05491b56-bea6-436c-bb2d-04d67ec546a4 | 1 | True | 2017-06-27T15:21:23.993Z | Initial relative | In Progress | | | | 1 | | False | | | 131072 | Not Activated | False | 1
73084 | 4cb5d794-3191-4d18-bf08-aa3c67e9f53a | 1 | True | 2017-12-20T13:29:30.223Z | renewal relative | Certified | 2015-11-04T23:00:00Z | 2018-11-04T23:59:00Z | 2018-10-04T23:59:00Z | 1 | | False | | | 131072 | Not Activated | False | 0
128339 | a9bf53a1-3060-43ba-852a-85ea3414101e | 1 | True | 2017-12-20T13:54:52.7Z | Initial relative | In Progress | | | | 1 | | False | | | 131072 | Not Activated | False | 1
191564 | 4cb5d794-3191-4d18-bf08-aa3c67e9f53a | 1 | True | 2017-12-20T13:29:30.223Z | Initial relative | In Progress | | | | 1 | | False | | | 131072 | Not Activated | False | 1
110211 | 0ccd9922-85fa-45de-bd87-257b77e2a5a3 | 1 | True | 2018-04-25T08:27:00Z | Initial relative | In Progress | | | | 0 | 2010-12-31T23:00:00Z | False | 2010-12-31T23:00:00Z | 2010-12-31T23:00:00Z | 4 | Approved | False | 1
203012 | a9bf53a1-3060-43ba-852a-85ea3414101e | 1 | True | 2017-12-20T13:54:52.7Z | Initial relative | In Progress | | | | 0 | 2018-02-07T14:31:23.25Z | False | 2018-02-07T14:31:22.943Z | 2018-02-07T14:31:00Z | 4 | Approved | False | 1
81973 | 4cb5d794-3191-4d18-bf08-aa3c67e9f53a | 1 | True | 2017-12-20T13:29:30.223Z | Initial relative | Expired | 2015-02-25T23:00:00Z | 2015-02-25T23:59:00Z | | 0 | 2015-02-26T06:00:00Z | False | 2015-02-26T06:00:00Z | 2015-02-26T06:00:00Z | 64 | Completed | False | 0
72012 | b39e8cbe-3030-4119-ac04-af5d623f443b | 1 | True | 2017-06-27T15:20:31.88Z | Initial relative | In Progress | | | | 1 | | False | | | 131072 | Not Activated | False | 1
93502 | dc28893a-5fdc-4fd2-b394-4cec5fc5a5bb | 1 | True | 2017-06-27T15:25:28.167Z | Initial relative | Certified (Renewal In Progress)/Past Due | 2014-06-04T23:00:00Z | 2014-06-04T23:59:00Z | | 0 | 2014-06-05T05:00:00Z | False | 2014-06-04T05:00:00Z | 2014-06-04T05:00:00Z | 64 | Completed | False | 0
128588 | dc28893a-5fdc-4fd2-b394-4cec5fc5a5bb | 1 | True | 2017-06-27T15:25:28.167Z | Initial relative | Certified | 2016-09-01T23:00:00Z | 2016-09-01T23:59:00Z | | 0 | 2016-09-02T05:00:00Z | False | 2016-09-01T05:00:00Z | 2016-09-01T05:00:00Z | 64 | Completed | False | 1
对于一些 user_id 和 cert_object_id 有多行：
select * from import.vw_rpt_certification where user_id = '81634' and cert_object_id = '4cb5d794-3191-4d18-bf08-aa3c67e9f53a';
user_id | cert_object_id | version | cert_is_active | cert_modify_dt | period_type | user_cert_status | first_period_completion_date | period_expiration_date | period_due_date | user_lo_active | user_lo_last_action_dt | cert_is_on_hold | user_lo_assigned_dt | user_lo_last_modified_dt | user_lo_status_id | user_lo_status | user_cert_is_archived | is_current_period
---------+--------------------------------------+---------+----------------+--------------------------+------------------+------------------+------------------------------+------------------------+----------------------+----------------+--------------------------+-----------------+--------------------------+--------------------------+-------------------+----------------+-----------------------+-------------------
81634 | 4cb5d794-3191-4d18-bf08-aa3c67e9f53a | 1 | True | 2017-12-20T13:29:30.223Z | renewal relative | Certified | 2015-04-22T23:00:00Z | 2018-01-26T23:59:00Z | | 0 | 2018-02-21T12:45:49.153Z | False | 2018-02-21T12:37:56.473Z | 2018-02-21T12:46:00Z | 64 | Completed | False | 1
81634 | 4cb5d794-3191-4d18-bf08-aa3c67e9f53a | 1 | True | 2017-12-20T13:29:30.223Z | Initial relative | Certified | 2015-04-22T23:00:00Z | 2015-04-22T23:59:00Z | | 0 | 2015-04-23T05:00:00Z | False | 2015-04-23T05:00:00Z | 2017-09-28T23:02:00Z | 64 | Completed | False | 0
81634 | 4cb5d794-3191-4d18-bf08-aa3c67e9f53a | 1 | True | 2017-12-20T13:29:30.223Z | renewal relative | Certified | 2015-04-22T23:00:00Z | 2021-04-22T23:59:00Z | 2021-03-22T23:59:00Z | 1 | | False | | | 131072 | Not Activated | False | 0
对于这些情况，我必须选择 period_expiration_date 列的值较高的行（该列也可以是空字符串）。
我这样试过：
with s1 as (
select distinct
user_id,
cert_object_id,
COALESCE(nullif(period_expiration_date,''), NULL)::timestamptz as ped
from import.vw_rpt_certification
group by user_id, cert_object_id, ped
), s2 as (
select dd.*, max(ped)
from s1 dd
group by dd.user_id, dd.cert_object_id, dd.ped
)
select * from s2;
user_id | cert_object_id | ped | max
---------+--------------------------------------+------------------------+------------------------
81634 | 4cb5d794-3191-4d18-bf08-aa3c67e9f53a | 2021-04-23 01:59:00+02 | 2021-04-23 01:59:00+02
81634 | 4cb5d794-3191-4d18-bf08-aa3c67e9f53a | 2018-01-27 00:59:00+01 | 2018-01-27 00:59:00+01
81634 | 4cb5d794-3191-4d18-bf08-aa3c67e9f53a | 2015-04-23 01:59:00+02 | 2015-04-23 01:59:00+02
但是我有点迷茫，对此有什么帮助吗？
我想生成一个 table 与 import.vw_rpt_certification 相同的列，但每对夫妇只保留一行 (user_id, cert_object_id)
这里为什么不用ROW_NUMBER:
WITH cte AS (
SELECT *,
ROW_NUMBER() OVER (PARTITION BY user_id, cert_object_id
ORDER BY period_expiration_date DESC) rn
FROM import.vw_rpt_certification
)
SELECT *
FROM cte
WHERE rn = 1;
试试这个：
Select user_id, cert_object_id, period_expiration_date
FROM
(
Select * ,
ROW_NUMBER() OVER(partition by user_id, cert_object_id
ORDER by period_expiration_date desc) as rnk
from import.vw_rpt_certification
)a
WHERE rnk = 1;
在 Postgres 中，distinct on 通常是最好的方法：
select distinct on (user_id, cert_object_id) rc.*
from import.vw_rpt_certification rc
order by user_id, cert_object_id,
period_expiration_date desc;
这可以直接使用 (user_id, cert_object_id, period_expiration_date) 上的索引。
我有这个table:
abs=# \d import.vw_rpt_certification
Table "import.vw_rpt_certification"
Column | Type | Collation | Nullable | Default
------------------------------+------+-----------+----------+---------
user_id | text | | |
cert_object_id | text | | |
version | text | | |
cert_is_active | text | | |
cert_modify_dt | text | | |
period_type | text | | |
user_cert_status | text | | |
first_period_completion_date | text | | |
period_expiration_date | text | | |
period_due_date | text | | |
user_lo_active | text | | |
user_lo_last_action_dt | text | | |
cert_is_on_hold | text | | |
user_lo_assigned_dt | text | | |
user_lo_last_modified_dt | text | | |
user_lo_status_id | text | | |
user_lo_status | text | | |
user_cert_is_archived | text | | |
is_current_period | text | | |
select * from import.vw_rpt_certification limit 10;
user_id | cert_object_id | version | cert_is_active | cert_modify_dt | period_type | user_cert_status | first_period_completion_date | period_expiration_date | period_due_date | user_lo_active | user_lo_last_action_dt | cert_is_on_hold | user_lo_assigned_dt | user_lo_last_modified_dt | user_lo_status_id | user_lo_status | user_cert_is_archived | is_current_period
---------+--------------------------------------+---------+----------------+--------------------------+------------------+------------------------------------------+------------------------------+------------------------+----------------------+----------------+-------------------------+-----------------+--------------------------+--------------------------+-------------------+----------------+-----------------------+-------------------
109485 | 05491b56-bea6-436c-bb2d-04d67ec546a4 | 1 | True | 2017-06-27T15:21:23.993Z | Initial relative | In Progress | | | | 1 | | False | | | 131072 | Not Activated | False | 1
73084 | 4cb5d794-3191-4d18-bf08-aa3c67e9f53a | 1 | True | 2017-12-20T13:29:30.223Z | renewal relative | Certified | 2015-11-04T23:00:00Z | 2018-11-04T23:59:00Z | 2018-10-04T23:59:00Z | 1 | | False | | | 131072 | Not Activated | False | 0
128339 | a9bf53a1-3060-43ba-852a-85ea3414101e | 1 | True | 2017-12-20T13:54:52.7Z | Initial relative | In Progress | | | | 1 | | False | | | 131072 | Not Activated | False | 1
191564 | 4cb5d794-3191-4d18-bf08-aa3c67e9f53a | 1 | True | 2017-12-20T13:29:30.223Z | Initial relative | In Progress | | | | 1 | | False | | | 131072 | Not Activated | False | 1
110211 | 0ccd9922-85fa-45de-bd87-257b77e2a5a3 | 1 | True | 2018-04-25T08:27:00Z | Initial relative | In Progress | | | | 0 | 2010-12-31T23:00:00Z | False | 2010-12-31T23:00:00Z | 2010-12-31T23:00:00Z | 4 | Approved | False | 1
203012 | a9bf53a1-3060-43ba-852a-85ea3414101e | 1 | True | 2017-12-20T13:54:52.7Z | Initial relative | In Progress | | | | 0 | 2018-02-07T14:31:23.25Z | False | 2018-02-07T14:31:22.943Z | 2018-02-07T14:31:00Z | 4 | Approved | False | 1
81973 | 4cb5d794-3191-4d18-bf08-aa3c67e9f53a | 1 | True | 2017-12-20T13:29:30.223Z | Initial relative | Expired | 2015-02-25T23:00:00Z | 2015-02-25T23:59:00Z | | 0 | 2015-02-26T06:00:00Z | False | 2015-02-26T06:00:00Z | 2015-02-26T06:00:00Z | 64 | Completed | False | 0
72012 | b39e8cbe-3030-4119-ac04-af5d623f443b | 1 | True | 2017-06-27T15:20:31.88Z | Initial relative | In Progress | | | | 1 | | False | | | 131072 | Not Activated | False | 1
93502 | dc28893a-5fdc-4fd2-b394-4cec5fc5a5bb | 1 | True | 2017-06-27T15:25:28.167Z | Initial relative | Certified (Renewal In Progress)/Past Due | 2014-06-04T23:00:00Z | 2014-06-04T23:59:00Z | | 0 | 2014-06-05T05:00:00Z | False | 2014-06-04T05:00:00Z | 2014-06-04T05:00:00Z | 64 | Completed | False | 0
128588 | dc28893a-5fdc-4fd2-b394-4cec5fc5a5bb | 1 | True | 2017-06-27T15:25:28.167Z | Initial relative | Certified | 2016-09-01T23:00:00Z | 2016-09-01T23:59:00Z | | 0 | 2016-09-02T05:00:00Z | False | 2016-09-01T05:00:00Z | 2016-09-01T05:00:00Z | 64 | Completed | False | 1
对于一些 user_id 和 cert_object_id 有多行：
select * from import.vw_rpt_certification where user_id = '81634' and cert_object_id = '4cb5d794-3191-4d18-bf08-aa3c67e9f53a';
user_id | cert_object_id | version | cert_is_active | cert_modify_dt | period_type | user_cert_status | first_period_completion_date | period_expiration_date | period_due_date | user_lo_active | user_lo_last_action_dt | cert_is_on_hold | user_lo_assigned_dt | user_lo_last_modified_dt | user_lo_status_id | user_lo_status | user_cert_is_archived | is_current_period
---------+--------------------------------------+---------+----------------+--------------------------+------------------+------------------+------------------------------+------------------------+----------------------+----------------+--------------------------+-----------------+--------------------------+--------------------------+-------------------+----------------+-----------------------+-------------------
81634 | 4cb5d794-3191-4d18-bf08-aa3c67e9f53a | 1 | True | 2017-12-20T13:29:30.223Z | renewal relative | Certified | 2015-04-22T23:00:00Z | 2018-01-26T23:59:00Z | | 0 | 2018-02-21T12:45:49.153Z | False | 2018-02-21T12:37:56.473Z | 2018-02-21T12:46:00Z | 64 | Completed | False | 1
81634 | 4cb5d794-3191-4d18-bf08-aa3c67e9f53a | 1 | True | 2017-12-20T13:29:30.223Z | Initial relative | Certified | 2015-04-22T23:00:00Z | 2015-04-22T23:59:00Z | | 0 | 2015-04-23T05:00:00Z | False | 2015-04-23T05:00:00Z | 2017-09-28T23:02:00Z | 64 | Completed | False | 0
81634 | 4cb5d794-3191-4d18-bf08-aa3c67e9f53a | 1 | True | 2017-12-20T13:29:30.223Z | renewal relative | Certified | 2015-04-22T23:00:00Z | 2021-04-22T23:59:00Z | 2021-03-22T23:59:00Z | 1 | | False | | | 131072 | Not Activated | False | 0
对于这些情况，我必须选择 period_expiration_date 列的值较高的行（该列也可以是空字符串）。
我这样试过：
with s1 as (
select distinct
user_id,
cert_object_id,
COALESCE(nullif(period_expiration_date,''), NULL)::timestamptz as ped
from import.vw_rpt_certification
group by user_id, cert_object_id, ped
), s2 as (
select dd.*, max(ped)
from s1 dd
group by dd.user_id, dd.cert_object_id, dd.ped
)
select * from s2;
user_id | cert_object_id | ped | max
---------+--------------------------------------+------------------------+------------------------
81634 | 4cb5d794-3191-4d18-bf08-aa3c67e9f53a | 2021-04-23 01:59:00+02 | 2021-04-23 01:59:00+02
81634 | 4cb5d794-3191-4d18-bf08-aa3c67e9f53a | 2018-01-27 00:59:00+01 | 2018-01-27 00:59:00+01
81634 | 4cb5d794-3191-4d18-bf08-aa3c67e9f53a | 2015-04-23 01:59:00+02 | 2015-04-23 01:59:00+02
但是我有点迷茫，对此有什么帮助吗？
我想生成一个 table 与 import.vw_rpt_certification 相同的列，但每对夫妇只保留一行 (user_id, cert_object_id)
这里为什么不用ROW_NUMBER:
WITH cte AS (
SELECT *,
ROW_NUMBER() OVER (PARTITION BY user_id, cert_object_id
ORDER BY period_expiration_date DESC) rn
FROM import.vw_rpt_certification
)
SELECT *
FROM cte
WHERE rn = 1;
试试这个：
Select user_id, cert_object_id, period_expiration_date
FROM
(
Select * ,
ROW_NUMBER() OVER(partition by user_id, cert_object_id
ORDER by period_expiration_date desc) as rnk
from import.vw_rpt_certification
)a
WHERE rnk = 1;
在 Postgres 中，distinct on 通常是最好的方法：
select distinct on (user_id, cert_object_id) rc.*
from import.vw_rpt_certification rc
order by user_id, cert_object_id,
period_expiration_date desc;
这可以直接使用 (user_id, cert_object_id, period_expiration_date) 上的索引。