


How to Retrieve the Latest Quantity per ID and Timestamp in Oracle SQL?
Jan 21, 2025 pm 03:42 PMOracle SQL: Extracting the Most Recent Quantity for Each ID
This guide demonstrates how to efficiently retrieve the latest quantity for each unique ID from a table containing timestamped data in Oracle SQL.
The core approach involves a nested query strategy:
SELECT id, MAX(ts) AS "DATE", MAX(quantity) AS "QUANTITY" FROM ( SELECT id, ts, RANK() OVER (PARTITION BY id ORDER BY ts DESC) AS rnk, quantity FROM your_table_name ) ranked_data WHERE rnk = 1 GROUP BY id;
This query operates as follows:
-
Inner Query (ranked_data): This subquery uses the
RANK()
window function to assign a rank to each row within eachid
group, ordered by the timestamp (ts
) in descending order. The latest record for eachid
receives a rank of 1. -
Outer Query: This query filters the results from the inner query, selecting only those rows with
rnk = 1
(the latest records). It then groups the results byid
and usesMAX()
to retrieve the corresponding timestamp and quantity. Note that usingMAX(quantity)
withGROUP BY id
is appropriate assuming that the latest timestamp also implies the latest quantity; if there could be multiple rows with the same latest timestamp but different quantities, a different aggregation method might be needed (likeFIRST_VALUE
in a more complex query).
Enhancements:
1. Time-Based Filtering: To restrict results to a specific time window (e.g., the last XX minutes), add a WHERE
clause to the inner query:
WHERE ts >= SYSTIMESTAMP - INTERVAL 'XX' MINUTE
2. Joining with Another Table: To incorporate data from another table (e.g., an id_table
with additional ID information), use a JOIN
in the outer query:
SELECT id || '-' || idname AS "ID-IDNAME", MAX(ts) AS "DATE", MAX(quantity) AS "QUANTITY" FROM ( SELECT id, ts, RANK() OVER (PARTITION BY id ORDER BY ts DESC) AS rnk, quantity FROM your_table_name ) ranked_data INNER JOIN id_table ON ranked_data.id = id_table.id WHERE rnk = 1 GROUP BY id || '-' || idname;
Remember to replace your_table_name
and id_table
with your actual table names. This refined approach provides a robust and flexible solution for retrieving the most recent quantity data in Oracle SQL.
The above is the detailed content of How to Retrieve the Latest Quantity per ID and Timestamp in Oracle SQL?. For more information, please follow other related articles on the PHP Chinese website!

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