3/29/2026 at 1:28:45 PM
Author here.I had the idea of building a working Chess game using purely SQL.
The chess framing is a bit of a trojan horse, honestly. The actual point is that SQL can represent any stateful 2D grid. Calendars, heatmaps, seating plans, game of life. The schema is always the same: two coordinate columns and a value. The pivot query doesn't change.
A few people have asked why not just use a 64-char string or an array type. You could! But you lose all the relational goodness: joins, aggregations, filtering by piece type. SELECT COUNT(*) FROM board WHERE piece = '♙' just works.
by upmostly
4/1/2026 at 5:29:10 PM
Yup. Works even better with R*Trees[1]. Great article btw!by andersmurphy
4/2/2026 at 1:05:13 AM
One of the things that LLMs "excel" at, pun very much intended, is this exact pattern - creating filtered aggregates for a finite set of columns, and using this at the end of a CTE!OP's example, for reference, was:
SELECT rank,
MAX(CASE WHEN file = 1 THEN COALESCE(piece, '·') END) AS a,
MAX(CASE WHEN file = 2 THEN COALESCE(piece, '·') END) AS b,
MAX(CASE WHEN file = 3 THEN COALESCE(piece, '·') END) AS c,
MAX(CASE WHEN file = 4 THEN COALESCE(piece, '·') END) AS d,
The broader pattern is, in successive CTEs:
1. Group by Date w/ Aggregates
2. "Melt" to [optional groupings +] month + measure_name + value tuples:
select group, month, '# Bookings' as measure_name, num_bookings as value from base_data
UNION ALL
select group, month, 'Revenue', total_revenue from base_data
MAX(CASE WHEN month = '2019-01' THEN value END) AS "2019-01",
MAX(CASE WHEN month = '2019-02' THEN value END) AS "2019-02",
MAX(CASE WHEN month = '2019-03' THEN value END) AS "2019-03",
And while the column breakouts are painful to type out by hand - they're very amenable to LLM generation!
by btown
4/1/2026 at 8:35:09 AM
Great showcase. Cool to see how any 2d state can be presented with enough work.Just FYI your statement for the checkmate state in the opera game appears to be incorrect
by jollygoodshow
4/1/2026 at 8:37:19 AM
Thank you, and thanks for highlighting that. I'll take a look now.by upmostly
4/1/2026 at 7:34:07 AM
Technically you can model anything in SQL including execution of any Turing complete languageby andoando
4/1/2026 at 9:57:48 AM
Yes, but OP wants to preserve the relational goodness.by eru
4/1/2026 at 10:03:18 PM
I've done huge sparse matrix math with SQL before. It parallelizes well like you'd expect.by traderj0e
4/1/2026 at 6:40:33 AM
SQL can make 2D data, but it extremely bad at it. It’s a good opportunity to wonder whether this part can be improved.“Pivot tables”: I often have a list of dates, then categories that I want to become columns. SQL can’t do that so there is a technique of spreading values to each column then doing a MAX of each value per date. It is clumsy and verbose but works perfectly… as long as categories are known in advance and fixed. There should be an SQL instruction to pivot those rows into columns.
Example: SELECT date, category, metric; -- I want to show 1 row per date only, with each category as a column.
``` SELECT date,
MAX( CASE category WHEN ‘page_hits’ THEN metric END ) as “Page Hits”,
MAX( CASE category WHEN ‘user_count’ THEN metric END ) as “User Count”
GROUP BY date;
^ Without MAX and GROUP BY: 2026-03-30 Value1 NULL 2026-03-30 NULL Value2 2026-03-31 Value1 NULL (etc) The MAX just merges all rows of the same date. ```
SQL should just have an instruction like: SELECT date, PIVOT(category, metric); to display as many columns as categories.
This thought should be extended for more than 2 dimensions.
by eastbound
4/1/2026 at 7:24:35 AM
DuckDB and Microsoft Access (!) have a PIVOT keyword (possibly others too). The latter is of course limited but the former is pretty robust - I've been able to use it for all I've needed.by tn1
4/1/2026 at 11:58:35 AM
PostgresSQL"crosstab ( source_sql text, category_sql text ) → setof record"
https://www.postgresql.org/docs/current/tablefunc.html
VIA https://www.beekeeperstudio.io/blog/how-to-pivot-in-postgres... as a current googlable reference/guide
by amichal
4/1/2026 at 5:30:28 PM
> SQL can make 2D data, but it extremely bad at it. It’s a good opportunity to wonder whether this part can be improved.R*Trees are what you are looking for. The sqlite implementation supports up to 5 dimensions.
by andersmurphy
4/1/2026 at 8:59:22 PM
in sqlite you can do it with FILTER: $ sqlite :memory:
create table t (product,revenue, year);
insert into t values ('a',10,2020),('b',14,2020),('c',24,2020),('a',20,2021),('b',24,2021),('c',34,2021);
select product,sum(revenue) filter (where year=2020) as '2020',sum(revenue) filter (where year=2021) as '2021' from t group by product;by h3lp
4/1/2026 at 4:28:14 PM
Can you comment on whether you wrote the article yourself or used an LLM for it? To me it reads human (in a maybe slightly overly-punchy, LinkedIn-esque way), but a lot of folks are keying on the choppiness and exclusion chains and concluding it's AI-written.I'm interested in whether others are oversensitive or I'm not sensitive enough... :)
by mwigdahl
4/1/2026 at 4:42:50 PM
They definitely used an LLM for itby slopinthebag