ClickHouse 26.5: SQL Compatibility Improvements

Mark Needham

ClickHouse 26.5 ships several SQL compatibility improvements alongside other new features. In this video, Mark runs through the SQL additions using ClickHouse Local.

• url_base setting — set a base URL once and reference just the filename in URL table function queries
• Negative LIMIT BY — use LIMIT -N BY column to return the bottom N rows per group instead of the top N
• UNNEST — SQL-standard alias for arrayJoin to explode arrays into rows
• STDDEV — alias for stddevSamp
• STRING_AGG — alias for groupConcat, with optional delimiter
• array_to_string — alias for arrayStringConcat
• Bare function names in higher-order functions — pass notEmpty or upper directly instead of writing a full lambda

More from the 26.5 release: https://clickhouse.com/blog/clickhouse-release-26-5