如何将组内最大值的行设置为真 sql

Question

I have a table similar to this:

ID	ORDER	AGE
12	34	50
99	41	17
12	34	24
99	42	12
12	33	15
12	33	38

I would like to look at the ID column, where if the ORDER value is the max value within the ID group, then to set it as TRUE, and the others as FALSE.

I tried to do

SELECT ID, ORDER,
CASE WHEN ORDER = MAX(ORDER) THEN TRUE ELSE FALSE END AS ACTIVE
FROM MY_TABLE
GROUP BY ID, ORDER;

But that seems to just set every ACTIVE value to true.

Ultimately I am trying to end up with a table like

ID	ORDER	AGE	ACTIVE
12	34	50	TRUE
99	41	17	FALSE
12	34	24	TRUE
99	42	12	TRUE
12	33	15	FALSE
12	33	38	FALSE

What would be the best way to achieve this? Thanks!

Answer 1

Use MAX() window function:

SELECT ID, ORDER, AGE,
       ORDER = MAX(ORDER) OVER (PARTITION BY ID) AS ACTIVE
FROM MY_TABLE;

Answer 2

You will want to rank the rows using row_number. Order by order and partition by id . This will provide you with a rank value where you can set the Active flag where rank = 1 .

https://docs.snowflake.com/en/sql-reference/functions/row_number.html