Markus Winand

Teaching is about making students reach the same level of understanding as the teacher—but with less mental effort. This allows students to put their mental efforts into growing beyond their teachers.

Charts on modern-sql.com are updated for DuckDB 2.0.0 (and MySQL 26.10, but that did not affect any chart).

If you ignore concurrency, everything is simple.

"PingCAP's engineers paste customers' production credentials into Jira tickets." Security problems are often rooted in an internal "non-production" system. Apparently 10.6 TB of data was copied from various systems at PingCAP (TiDB). fulcrumsec.vg/pingcap/

Universal qualities of programming languages: (1) Support nested block comments (2) User-configurable string delimiter To be continued...

YES, they are using AI to summarize everything into nothing... YET, they use AI to make their spam messages longer.

Universal qualities of programming languages: (1) Support nested block comments To be continued...

The bank always wins! Nowadays: The token seller always wins!

rewritey.com/ "Rewrite multi-join SQL into faster plans. Analyze query shape and workload overlap to find reusable intermediates." Maybe worth a try if you have aggregating queries with many joins.

I guess even the print edition of SQL Performance Explained is more environmental friendly as one day of agentic AI usage...

€10 for a frontier AI subscription are gone in one workday. €10 for my book SQL Performance Explained has a lasting impact on you*. sql-performance-explained.com Learning fundamentals that don't change always has a lasting effect. * you also need to read it, which takes about 1 day ;)

Venn diagrams for teaching relational joins are plain wrong. I explain why in this new article. thegresqlpost.org/articles/joi...

Oracle Just Halved Its Always Free ARM Limits https://www.cnelecar.com/blog/oracle-always-free-arm-limits-cut-2026/ https://news.ycombinator.com/item?id=49183750

There's much more to defining primary keys than using surrogate id columns @winand.at introduces Structured Primary Keys These are based on foreign keys plus the columns needed for uniqueness Using these can give big performance and functional benefits

peter.eisentraut.org/blog/2026/06...

What happens, when the race to to bottom hits the bottom? Asking for a friend.

New post: Structured Primary Keys For consistency and performance. modern-sql.com/blog/2026-06...

Taking a walk to think in peace can solve quite some problems.

The perfect guide to the oracle optimizer blogs.oracle.com/optimizer/or... Kudos @vldbb.bsky.social

Once I though Bitcoin is the greatest possible waste of energy...

The SQL/JSON Path item-method .keyvalue() has an interesting history in the Oracle Database. modern-sql.com/caniuse/keyv... In 23.26.2 it works, but not in ?( filter ) context.

MariaDB 12.3.2 was released last week. It is the first "stable" version of the long-term supported (LTS = 3 years) 12.3 branch. An SQL dialect enhancement is the IS JSON predicate. Also: a bug I reported is fixed (MDEV-38835). All charts on modern-sql.com are updated. #SQL #JSON #MariaDB

MariaDB 12.3.2 was released last week. It is the first "stable" version of the long-term supported (LTS = 3 years) 12.3 branch. An SQL dialect enhancement is the IS JSON predicate. Also: a bug I reported is fixed (MDEV-38835). All charts on modern-sql.com are updated. #SQL #JSON #MariaDB

ORDER BY Has Come a Long Way modern-sql.com/blog/2026-05... The ORDER BY clause is surely one of the best-known SQL clauses. Yet there are a number of common misunderstandings that are worth clearing up. For that, the article walks you through the evolution of the ORDER BY clause the SQL standard.

dBase: 1979-2026 | Discussion

Should these functions return the same value? SELECT ROW_NUMBER() OVER (ORDER BY x), ROW_NUMBER() OVER (ORDER BY x) FROM ... What about when many rows have the same value for X? According to the #SQL standard: yes @winand.at investigates

Order-equivalent OVER clauses modern-sql.com/blog/2026-03... About an important but rarely appreciated aspect when using multiple OVER clauses in a single query.

AI is the future? Well, if we cannot buy computers anymore, it sounds like stone age to me.

hakibenita.com/postgres-row...

i love databases i love databases i love databases writing sql is fun writing sql is fun writing sql is fun

Reading about LLM's accuracy to produce SQL queries I ran into llm-benchmark.tinybird.live. According to their study, the average accuracy/exactness is ~50%. So half of the time models returns a query than runs but returns a wrong answer. How are people using this in production?

I wonder when we see the first OpenClaw worm, if there isn't one already. Switching off your Mac Mini won't stop it.

Think you know about #SQL performance? Take this 3-minute indexing quiz by @winand.at A simple test that 60% fail! buff.ly/5C4XZ7N Did you pass? Let us know how you did!

Claude's C Compiler vs. GCC | Discussion

SQL Comments, Please! modern-sql.com/caniuse/comm...

What is random, but actually useful, things you wish you had a SQL interface for?

Infinite Recursion Guards modern-sql.com/caniuse/with... With recursive is the only SQL construct that is not guaranteed to terminate, eventually. As the DBMS is typically a very crucial system, infinite loops must be prevented at all times. See how various SQL systems help you.

Time to re-watch The Terminator (1984)

Latencies are often misunderstood. Also the IO latency in cloud environments, which are often many factors higher as on local discs (during development).

Probably coming in PostgreSQL 19, btw.