D1 limits page: missing compound SELECT (5) and result-set column (100) limits; function-argument limit listed as 32 but D1 allows 127 #34596

Disclaimer: Claude helped me setup the content for this but it describes real issues I encountered while developing. Would be nice for D1 docs to have those limitations mentioned somewhere so LLMs at least try to avoid/verify what they do.

Existing documentation URL(s)

https://developers.cloudflare.com/d1/platform/limits/ (shows "Last updated Oct 24, 2026")

Problem

The limits table leaves out two limits that D1 enforces, and gets one number wrong. We found this when a query
that passed our local tests (bun:sqlite, which uses SQLite's default limits) failed in production with
too many terms in compound SELECT. We checked the limits page first and the limit isn't on it.

Measured on 2026-10-25 against a remote D1 database with read-only queries through wrangler d1 execute --remote
(wrangler 4.149.0). Local D1 (--local) gives exactly the same results:

Reproduction

-- 5 terms work, 6 fail
select 1 union all select 1 union all select 1 union all select 1 union all select 1;
select 1 union all select 1 union all select 1 union all select 1 union all select 1 union all select 1;
-- → too many terms in compound SELECT: SQLITE_ERROR [code: 7500]

-- 100 columns work, 101 fail
select 1,2,3, … ,101;
-- → too many columns in result set: SQLITE_ERROR

-- 33 and 127 arguments work, 128 fails (the page says 32)
select max(1,2, … ,127); -- ok
select max(1,2, … ,128);
-- → too many arguments on function max at offset 7: SQLITE_ERROR

What changes are you suggesting?

• Add Maximum terms in a compound SELECT: 5.
• Change "columns per table" to cover result sets too, e.g. Maximum columns in a table or result set: 100.
  SQLite's SQLITE_LIMIT_COLUMN also covers the terms in ORDER BY, GROUP BY and the SET clause of an
  UPDATE, so those may be worth stating too.
• Change Maximum arguments per SQL function to 127, or explain where 32 applies.
• Ideally, list every sqlite3_limit() value D1 sets. These limits are far lower than SQLite's defaults
  (e.g. 500 compound terms, 2000 columns), and the usual way to run D1 queries in unit tests, a local SQLite
  library, uses those defaults. So the published table is the only warning a developer gets before a query
  fails in production.

Additional information

No response