Add BigQuery -> ClickHouse SQL reference#6224
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dhtclk
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May 14, 2026
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Just a few comments (mostly British spellings)
Co-authored-by: Dominic Tran <dominic.tran@clickhouse.com>
Blargian
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May 14, 2026
Co-authored-by: Shaun Struwig <41984034+Blargian@users.noreply.github.com>
…e table notes to make it more clear they belong to the row above
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Blargian
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May 18, 2026
| | [`JSON`](https://cloud.google.com/bigquery/docs/reference/standard-sql/data-types#json_type) | [`JSON`](/sql-reference/data-types/newjson) or [`String`](/sql-reference/data-types/string) | `JSON` is preferred; `String` with [`JSONExtract*`](/sql-reference/functions/json-functions) accessors works as a fallback | | ||
| | [`NUMERIC`](https://cloud.google.com/bigquery/docs/reference/standard-sql/data-types#decimal_types) | [`Decimal(P, S)`](/sql-reference/data-types/decimal) | Sized variants `Decimal32(S)` / `Decimal64(S)` / `Decimal128(S)` are also available | | ||
| | [`RANGE`](https://cloud.google.com/bigquery/docs/reference/standard-sql/data-types#range_type) | No equivalent | Store `(start, end)` columns or a `Tuple(start, end)` | | ||
| | [`STRING`](https://cloud.google.com/bigquery/docs/reference/standard-sql/data-types#string_type) | [`String`](/sql-reference/data-types/string) | Optionally wrap in [`LowCardinality(String)`](/sql-reference/data-types/lowcardinality) for columns with few distinct values (enums, status codes, country codes). String functions are byte-based; the [String family](/sql-reference/functions/string-functions) has `UTF8` variants where relevant | |
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Feedback from Amy: We should probably flag this as a performance optimization. This might be because I'm in dark mode but I didn't realize those data types were actually links.
Blargian
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May 18, 2026
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| Location is a service-level decision in ClickHouse Cloud. |
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Feedback from Amy: decision? maybe configuration?
Blargian
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May 18, 2026
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| ## DDL statements {#ddl-statements} | ||
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| ### Schemas and databases {#ddl-schemas} |
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Feedback from Amy: missing the three part namespace callout
Blargian
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May 18, 2026
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| An engine and an `ORDER BY` are required for `MergeTree`-family tables; pick the columns that match the query access pattern. See [Sparse primary indexes](/guides/best-practices/sparse-primary-indexes). |
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Feedback from Amy: I think we need a sentence as to why order by is so crucial in clickhouse. it would make the partition comment make more sense. Also link out to what even is a mergetree
Blargian
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May 18, 2026
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| ### Roles {#dcl-roles} |
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Feedback from Amy: I think this table is unnecessary - I think you could just do a sentence and link to the create role/user docs
Blargian
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May 18, 2026
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| ### Pipe syntax {#pipe-syntax} |
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Feedback from Amy: you could just say we don't support this?
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Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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Summary
Adds a BigQuery to ClickHouse SQL reference guide
Checklist
Note
Low Risk
Documentation and CSS only; no application code, auth, or data paths.
Overview
Adds a dedicated BigQuery SQL translation reference at
/migrations/bigquery/sql-translation-referencewith side-by-side BigQuery vs ClickHouse mappings for types, DDL/DML/DCL, query syntax, operators, and function families (arrays, aggregates, windows, dates, strings, JSON).The BigQuery vs ClickHouse Cloud overview no longer embeds the full type table and long array/
UNNESTexamples; those sections now point to the reference. The BigQuery migration landing page lists the new doc, andcustom.scssintroduces.sql-translation-tablestyling for the comparison tables (including a three-column notes variant).Reviewed by Cursor Bugbot for commit 56e5806. Bugbot is set up for automated code reviews on this repo. Configure here.