获取每个 id 的最新记录

Question

I am trying to get a list of all users in a database. Then I have another table where I only have the users who are members.

The issue is that some of those who are members today, could have been customers, members or none of them earlier. So we could have duplicates.

What I want to do is to pick only the most recent record based on date column which is present in the database.

Here are the 2 tables output:

User table:

Users table

Members table: Members table

Want to left join the tables with keeping all the distinct records from users table and most matching records from members table with the most recent cd.value.

    WITH users AS(

SELECT
fullVisitorId AS Clientid

FROM `records`
WHERE
_TABLE_SUFFIX BETWEEN FORMAT_DATE('%Y%m%d',DATE_SUB(CURRENT_DATE(), INTERVAL 10 DAY))
AND
FORMAT_DATE('%Y%m%d',DATE_SUB(CURRENT_DATE(), INTERVAL 1 DAY))
AND
totals.visits = 1


), members As(

SELECT
MAX(date) AS date,
fullVisitorId AS Clientid,
cd.value AS CD_value,
cd.index AS CD_index

FROM `records`,
UNNEST(customDimensions) AS cd
WHERE
_TABLE_SUFFIX BETWEEN FORMAT_DATE('%Y%m%d',DATE_SUB(CURRENT_DATE(), INTERVAL 10 DAY))
AND
FORMAT_DATE('%Y%m%d',DATE_SUB(CURRENT_DATE(), INTERVAL 1 DAY))
AND
totals.visits = 1
AND
cd.index = 6
group by
Clientid,
CD_value,
CD_index


)

SELECT
users.ClientId AS clientId,
members.CD_value

from users


LEFT JOIN members ON users.ClientId = members.Clientid


group by
members.CD_value,
clientId


order by
clientId ASC

Answer 1

try by using row_number()

WITH users AS(

SELECT
fullVisitorId AS Clientid

FROM `records`
WHERE
_TABLE_SUFFIX BETWEEN FORMAT_DATE('%Y%m%d',DATE_SUB(CURRENT_DATE(), INTERVAL 10 DAY))
AND
FORMAT_DATE('%Y%m%d',DATE_SUB(CURRENT_DATE(), INTERVAL 1 DAY))
AND
totals.visits = 1


), members As(

SELECT
date AS date,
fullVisitorId AS Clientid,
cd.value AS CD_value,
cd.index AS CD_index,
row_number() over(partition by Clientid,
CD_value,
CD_index order by date desc) rn

FROM `records`,
UNNEST(customDimensions) AS cd
WHERE
_TABLE_SUFFIX BETWEEN FORMAT_DATE('%Y%m%d',DATE_SUB(CURRENT_DATE(), INTERVAL 10 DAY))
AND
FORMAT_DATE('%Y%m%d',DATE_SUB(CURRENT_DATE(), INTERVAL 1 DAY))
AND
totals.visits = 1
AND
cd.index = 6 


), m2 as ( select * from members where rn=1)

SELECT distinct
users.ClientId AS clientId,
m2.CD_value

from users  

LEFT JOIN m2 ON users.ClientId = m2.Clientid  


order by
clientId ASC