LIMIT n OFFSET offset_value BY expressions; During query processing, ClickHouse selects data ordered by sorting key. The sorting key is set explicitly using an ORDER BY clause or implicitly as a property of the table engine. Then ClickHouse applies LIMIT n BY expressions and returns the first n rows for each distinct combination of expressions.
A query with the LIMIT n BY expressions clause selects the first n rows for each distinct value of expressions . The key for LIMIT BY can contain any number of ...
28.02.2019 · If you would like to get the top 2 (or top 5, or top 100) actions a user has done, you might look for a solution that this: SELECT rs.id2, rs.id4, rs.v3 FROM ( SELECT id2, id4, v3, row_number () OVER (PARTITION BY id2, id4 ORDER BY v3 DESC) AS Rank FROM tbl ) …
14.07.2020 · I'm trying to aggregate over the results of a query with LIMIT BY. Building upon the example from docs, I'm running the following query: SELECT count() FROM limit_by LIMIT 1 BY id This query results in the following error: Code: 215. DB:...
[INTO OUTFILE filename] [FORMAT format] [LIMIT n BY columns]. All the clauses are optional, except for the required list of expressions immediately after ...
12.10.2017 · ClickHouse don't have optimization which allows skipping rows while reading first (or last) N rows ordered by primary key. So, results you see are expected. Even when you need to read first N rows, ordered by primary key, it's necessary to merge data from different parts, which is full scan if your query doesn't have limitation on date column or primary key.
Limits ; Amount of data on the host when using fast network storage, 10 GB, 8192 GB ; Amount of data on the host when using non-replicated network storage, 93 GB ...
09.03.2021 · LIMIT n OFFSET offset_value BY expressions; During query processing, ClickHouse selects data ordered by sorting key. The sorting key is set explicitly using an ORDER BY clause or implicitly as a property of the table engine. Then ClickHouse applies LIMIT n BY expressions and returns the first n rows for each distinct combination of expressions.