docs(sql): SAMPLE BY FILL - cross-column references for prev, fast-path and limitations#426
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docs(sql): SAMPLE BY FILL - cross-column references for prev, fast-path and limitations#426jovfer wants to merge 2 commits into
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Update the SAMPLE BY reference and the related cookbook recipes to match what the FILL fast path now accepts: - sample-by.md: list PREV(col) in the FILL options table, replace the outdated "fill strategies cannot be combined" rule with the actual PREV(col) and FILL(NONE) constraints, and rewrite the FROM-TO Limitations to drop "not compatible with FILL(PREV)" and "does not consider OFFSET". Note that keyed FROM-TO is supported when FROM/TO are constants and is rejected for bind-variable / function / arithmetic bounds. - fill-keyed-arbitrary-interval.md: scope the recipe to the bind-variable / function-bound case, since constant-bound keyed FROM-TO works natively. - fill-from-one-column.md: replace the "imagine this SQL was valid" framing with the actual FILL(PREV(col)) syntax and keep the window- function rewrite as the more flexible alternative for cases such as flagging filled rows.
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🚀 Build success! Latest successful preview: https://preview-426--questdb-documentation.netlify.app/docs/ Commit SHA: f0df257
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jovfer
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javier
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May 8, 2026
| (= `2025-12-31T23:00:00Z` UTC). | ||
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| `FROM-TO` can only be used on non-keyed SAMPLE BY queries (queries with no grouping columns other than the timestamp). | ||
| `FROM-TO` works with both non-keyed and keyed `SAMPLE BY` queries. Keyed queries emit one row per (bucket, key) combination across the full interval. Keyed `FROM-TO` requires `FROM`/`TO` to be constants; bind variables, function calls, or arithmetic expressions are rejected with _FROM-TO intervals are not supported for keyed SAMPLE BY queries_. |
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I think there is some punctuation problem here. I am not sure which the restrictions are
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it's poor formatting, anyway I'll delete the 3rd sentence here to avoid duplication with limitation sections as suggested below.
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Small comments, but otherwise ready to go
| - Only works with `ALIGN TO CALENDAR` (default alignment). | ||
| - Does not consider any specified `OFFSET`. | ||
| - Only for non-keyed `SAMPLE BY` (designated timestamp and aggregate columns only). See [Fill keyed queries with arbitrary intervals](/docs/cookbook/sql/time-series/fill-keyed-arbitrary-interval/) for a workaround. | ||
| - Keyed `FROM-TO` requires `FROM`/`TO` to be constants. Bind variables, |
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This is exactly the same we said above. I would keept it here under limitations, and would remove from aboive
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Summary
Refresh the SAMPLE BY FILL documentation to reflect what the fast-path implementation in questdb/questdb#6946 now accepts.
query/sql/sample-by.mdPREV(col)to the FILL options table and list its constraints (type match, no broadcast, no SYMBOL).FILL(NONE)rule.cookbook/sql/time-series/fill-keyed-arbitrary-interval.mdcookbook/sql/time-series/fill-from-one-column.mdFILL(PREV(col))syntax. Keep the window-function rewrite as the flexible alternative (e.g. flagging filled rows).Test plan
#from-to,#fill-options) still resolve.