您可以在 where 子句中使用分区更新表吗？

Question

I have a query:

SELECT *, ORDER = MAX(ORDER) OVER (PARTITION BY ID)
FROM MY TABLE

Where MY_TABLE is currently

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

I want the table to be updated as the result from the query to be

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

Is there a way to do this with an UPDATE statement.

I was trying

UPDATE MY_TABLE
SET RECENT = FALSE
WHERE ORDER <> MAX(ORDER) OVER (PARTITION BY ID);

But I am not sure how to incorporate the partition statement into the update.

Answer 1

Try this:

update my_table
set recent = false
where (id, order) not in (select id, max(order) from my_table group by 1); 

Answer 2

As suggested by @Tim Biegeleisen, running this as an update may not be the best idea. Rather than updating the table you could create a view over the top of it to always show the latest information, without needing to update the table. This removes the risk of the RECENT column going out of date between new values being added, and the update process being executed.

CREATE TABLE my_tbl (id NUMBER, "ORDER" NUMBER, age NUMBER);

INSERT INTO my_tbl VALUES 
(12, 34, 50),
(99, 41, 17),
(12, 34, 24),
(99, 42, 12),
(12, 33, 15),
(12, 33, 38);

CREATE OR REPLACE VIEW my_view AS
SELECT
    *,
    "ORDER" = MAX("ORDER") OVER (PARTITION BY ID) AS RECENT
FROM
    my_tbl
;

This gives the output:

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

Adding another row:

INSERT INTO my_tbl VALUES (12, 35, 51);

Gives:

ID	ORDER	AGE	RECENT
12	34	50	FALSE
99	41	17	FALSE
12	34	24	FALSE
99	42	12	TRUE
12	33	15	FALSE
12	33	38	FALSE
12	35	51	TRUE