英文:
How to change all values to the first in the sequence?
问题
我有3列：UserID，Channel和Order_Sequence。我希望根据用户ID的第一个序列来保留Channel列的第一个通道。我如何在SQL中获取输出列WANT？
英文:
I have 3 columns: UserID, Channel, and Order_Sequence. I want the Channel column to keep the first channel based on the first sequence of the user id. How can I get it to output the column WANT in sql?
答案1
得分: 2
你可以使用 first_value() 函数：
select t.*,
first_value(channel) over (partition by userid order by sequence) as want
from t;
英文:
You can use first_value():
select t.*,
first_value(channel) over (partition by userid order by sequence) as want
from t;
答案2
得分: 0
Using the good old correlated subquery approach
select t.*, (select channel from test where userid=t.userid and order_sequence=1) as want
from test t;
英文:
Using the good old correlated subquery approach
select t.*, (select channel from test where userid=t.userid and order_sequence=1) as want
from test t;
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