EXPLAIN EXTENDED

Most-linked posts?

1. GPT in 500 Lines of SQL
   10 people · 11 mentions · first linked 2024-01-01
2. Solving the Impossible Puzzle with PostgreSQL
   3 people · 3 mentions · first linked 2017-01-02
3. Drawing a snowflake in PostgreSQL
   3 people · 3 mentions · first linked 2013-01-10
4. A GIF decoder in SQL
   2 people · 2 mentions · first linked 2019-01-03
5. Finding the best starting word for Wordle using SQL
   2 people · 2 mentions · first linked 2022-01-28
6. /2009/09/29/adjacency-list-vs-nested-sets-mysql/
   2 people · 2 mentions · first linked 2011-01-28
7. PostgreSQL 8.4: sampling random rows
   2 people · 2 mentions · first linked 2010-05-30
8. Drawing fractals with PostgreSQL
   2 people · 2 mentions · first linked 2014-01-02

What Hacker News says?

1. B1FF_PSUVM · 2024-02-24Recommends

   "It's full of jewels", as someone almost said. E.g. The Sultan’s Riddle in SQL https://explainextended.com/2016/12/31/happy-new-year-8/

   Comment linking /2016/12/31/happy-new-year-8/

   on “GPT in 500 Lines of SQL”
2. thunderbong · 2024-02-24

   Submitted GPT in 500 Lines of SQL as a story · 1111 points

   HN discussion
3. jswinghammer · 2011-01-28

   Ok here is the search that first brought this issue to my attention: mysql spatial index example lft rgt I see the following order: 1: http://planet.mysql.com/entry/?id=23512 2: http://efreedom.com/Question/1-1743894/Mysql-Optimizing-Find... 3: http://explainextended.com/2009/09/29/adjacency-list-vs-nest... 4: http://stackoverflow.com/questions/1743894/mysql-optimizing-...

   Comment linking /2009/09/29/adjacency-list-vs-nested-sets-mysql/

   on “Google algorithm change launched”
4. niklas · 2009-11-21

   Submitted Awesome SQL blog as a story · 155 points

   HN discussion
5. alexggordon · 2015-07-21Recommends

   I always loved Snowflakes[0] in postgresql. That said though, almost anything could be visualized in postgresql because of the awesome geometric[1] functions that are natively supported. Someday when I'm bored, I might try doing something like the Mona Lisa in postgres. [0] http://explainextended.com/2013/12/31/happy-new-year-5/ [1] http://www.postgresql.org/docs/9.0/static/functions-geometry...

   Comment linking /2013/12/31/happy-new-year-5/

   on “Woah that is some wild postgresql”
6. ColinWright · 2022-01-08

   Submitted Implementing a quantum computer emulator in SQL as a story · 70 points

   HN discussion
7. davidjnelson · 2019-05-22

   Things like late row lookups in mysql that are not an issue in postgres https://explainextended.com/2011/02/11/late-row-lookups-inno...

   Comment linking /2011/02/11/late-row-lookups-innodb/

   on “ZetaSQL – A SQL Analyzer Framework from Google”
8. kungfooey · 2010-12-31

   Submitted Build a new year clock with an SQL query? Sure, why not as a story · 69 points

   HN discussion
9. hans_castorp · 2024-11-25

   With Postgres you can also generate fireworks http://explainextended.com/2009/12/31/happy-new-year/ or snowflakes: http://explainextended.com/2011/12/31/happy-new-year-3/ Or you can solve a Sudoku riddle in Oracle https://technology.amis.nl/2009/10/13/oracle-rdbms-11gr2-sol...

   Comment linking /2011/12/31/happy-new-year-3/

   on “SQLite: Outlandish Recursive Query Examples”
10. bacarter · 2014-01-02

    Submitted Drawing fractals with PostgreSQL as a story · 51 points

    HN discussion
11. gurkendoktor · 2022-05-09Recommends

    Ooohh, I didn't know this name for it, thanks. I somehow came across it as The Sultan's Riddle on the internet: https://explainextended.com/2016/12/31/happy-new-year-8/ I prefer this less sterile framing of it. It was the most fun that I ever had with a puzzle, so to anyone scrolling around on this page, I would recommend not jumping straight to the solution :)

    Comment linking /2016/12/31/happy-new-year-8/

    on ““I don't know the numbers”: a math puzzle”
12. thisisnotmyname · 2010-05-12

    Submitted Things SQL needs: MERGE JOIN that would seek as a story · 28 points

    HN discussion
13. pradocchia · 2009-11-21Recommends

    I like this style better than SQL for Smarties. Celko tries to stick with the ANSI standard, which is fine, but I much to prefer to know how to get the most out of each platform. Like here, http://explainextended.com/2009/09/ , he covers adjacency list vs. nested sets on MySQL, Postgres, Oracle and SQL Server. Different platforms, different optimal solutions. The man knows his database internals.

    Comment linking /2009/09/

    on “Awesome SQL blog”
14. MarkusWinand · 2014-07-10

    Submitted Xkcd comics which can illustrate programming questions as a story · 27 points

    HN discussion
15. wolfhumble · 2010-03-27

    > I was AMAZED how poorly Oracle performed in one certain use case (real time aggregation of a relatively large hierarchial database) Out of interest, what kind of hierarchial database was this? Something like this? http://explainextended.com/2009/09/28/adjacency-list-vs-nest...

    Comment linking /2009/09/28/adjacency-list-vs-nested-sets-oracle/

    on “NoSQL vs. RDBMS: Let the flames begin”
16. rnicholson · 2010-11-08

    Submitted Things in MySQL that won't work as expected as a story · 25 points

    HN discussion
17. whattheheckheck · 2025-04-08

    https://explainextended.com/2023/12/31/happy-new-year-15/

    Comment linking /2023/12/31/happy-new-year-15/

    on “Beyond Quacking: Deep Integration of Language Models and RAG into DuckDB”
18. MarkusWinand · 2024-01-05

    Submitted GPT in 500 Lines of SQL as a story · 9 points

    HN discussion
19. mmh0000 · 2025-06-17

    The creators understand it well. The math is pretty a lot, but, you can literally do it with pen and paper. There are plenty of blog[1] posts showing the process. Anyone claiming AI is a black box no one understands is a marketing-level drone trying to sell something that THEY don't understand. [1] https://explainextended.com/2023/12/31/happy-new-year-15/

    Comment linking /2023/12/31/happy-new-year-15/

    on “Claude Code feels like magic because it is iterative”
20. ColinWright · 2022-01-01

    Submitted Implementing a quantum computer emulator in SQL as a story · 8 points

    HN discussion
21. itsybitsycoder · 2013-05-08

    I believe I read that in Postgres the query planner does the same thing whether you use EXISTS/NOT EXISTS or IN/NOT IN. I don't think this is true, unless it's a very recent change. Here's a post from 2009 comparing NOT IN/NOT EXISTS/LEFT JOIN WHERE IS NULL for Postgres: http://explainextended.com/2009/09/16/not-in-vs-not-exists-v...

    Comment linking /2009/09/16/not-in-vs-not-exists-vs-left-join-is-null-postgresql/

    on “Learn SQL, dammit”
22. MWinther · 2010-05-30

    Submitted PostgreSQL 8.4: sampling random rows as a story · 8 points

    HN discussion
23. kogir · 2013-07-09

    You can actually do really fun (and fast!) things with dates by mapping them to geospatial types. For an example see: http://explainextended.com/2009/08/11/efficient-date-range-q... You can easily extend this map into more dimensions depending in your common use cases and the capability of your DB's spatial library.

    Comment linking /2009/08/11/efficient-date-range-query-sql-server/

    on “Show HN: Better SQL group by date”
24. j_baker · 2009-08-04

    Submitted Double thinking in SQL as a story · 8 points

    HN discussion
25. mmh0000 · 2024-02-28

    >> I've asked ChatGPT to write a VBScript function that returns false if the input is true and false if the input is false. <insert to-be-fair meme here> You purposefully asked GPT a trick question for which it likely has very little training data. No one would ever go on StackExchange et al. asking how to write a function that always returns false. So GPT had to take its training data on other, realistic questions…

    Comment linking /2023/12/31/happy-new-year-15/

    on “Ask HN: I don't use AI. What exactly am I missing out on?”
26. rmason · 2024-01-17

    Submitted Happy New Year: GPT in 500 Lines of SQL as a story · 6 points

    HN discussion
27. rstuart4133 · 2026-02-19

    For the LLM explainer, did you point Claude at this one? https://explainextended.com/2023/12/31/happy-new-year-15/ This page Claude assisted page rhymes with that one. Sorta.

    Comment linking /2023/12/31/happy-new-year-15/

    on “Show HN: Beautiful interactive explainers generated with Claude Code”
28. dajobe · 2024-01-01

    Submitted Happy New Year: GPT in 500 Lines of SQL as a story · 6 points

    HN discussion
29. quassnoi · 2011-04-12

    Sure, especially if you nest the sets using a datatype indexable with an R-Tree index: http://explainextended.com/2009/09/29/adjacency-list-vs-nest... However, nested sets is still very expensive to update which may be a deciding factor if your hierarchy is subject to frequent change (like, a folder-like structure with the folders being moved here and there) and you don't need to query for "all descendants" often.

    Comment linking /2009/09/29/adjacency-list-vs-nested-sets-mysql/

    on “Hierarchical Queries in MySQL (Function substitute for CONNECT BY)”
30. snagg · 2024-01-10

    Submitted GPT in 500 Lines of SQL as a story · 5 points

    HN discussion

Search all of HN for explainextended.com

Linked by the same people?

• LLitmuslitmus.com
• BBackblaze Blog | Cloud Storage & Cloud Backupblog.backblaze.com
• PPerconamysqlperformanceblog.com
• BBuffer: All-you-need social media toolkit for small businessesblog.bufferapp.com
• SSam Altmanblog.samaltman.com
• TTerence Edenshkspr.mobi
• RRands in Reposerandsinrepose.com
• AArmin Ronacherlucumr.pocoo.org