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doc: add note about table aliases in FOR UPDATE OF clause #22568

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doc: add note about table aliases in FOR UPDATE OF clause #22568

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4 changes: 4 additions & 0 deletions sql-statements/sql-statement-select.md
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Expand Up @@ -109,6 +109,10 @@ TableSample ::=
>
> Starting from v6.6.0, TiDB supports [Resource Control](/tidb-resource-control-ru-groups.md). You can use this feature to execute SQL statements with different priorities in different resource groups. By configuring proper quotas and priorities for these resource groups, you can gain better scheduling control for SQL statements with different priorities. When resource control is enabled, statement priority (`HIGH_PRIORITY`) will no longer take effect. It is recommended that you use [Resource Control](/tidb-resource-control-ru-groups.md) to manage resource usage for different SQL statements.

> **Note:**
>
> Starting from v8.5.6, TiDB supports using table aliases in the `FOR UPDATE OF` clause. To maintain backward compatibility, referencing the base table name when an alias is defined is still allowed, but it will trigger a warning advising you to use the explicit alias. When a query involves multiple tables with the same name across different databases (for example, `FROM db1.t, db2.t FOR UPDATE OF t`), TiDB now matches the target table from left to right based on the order in the `FROM` clause, rather than the current database context. To avoid ambiguity, it is recommended to specify the database name or use aliases in the `FOR UPDATE OF` clause.
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@gemini-code-assist gemini-code-assist bot Mar 16, 2026

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To improve clarity and align with the style guide, I suggest a few wording improvements. This makes the text more direct and easier for users to understand.

Specifically, this suggestion:

  • Rewords advising you to use for better conciseness (Style Guide line 24).
  • Changes the passive it is recommended to specify to it is recommended that you specify, which is more consistent with the style guide's preference for using the second person ("you") and avoiding passive voice (Style Guide lines 22, 43).
Suggested change
> Starting from v8.5.6, TiDB supports using table aliases in the `FOR UPDATE OF` clause. To maintain backward compatibility, referencing the base table name when an alias is defined is still allowed, but it will trigger a warning advising you to use the explicit alias. When a query involves multiple tables with the same name across different databases (for example, `FROM db1.t, db2.t FOR UPDATE OF t`), TiDB now matches the target table from left to right based on the order in the `FROM` clause, rather than the current database context. To avoid ambiguity, it is recommended to specify the database name or use aliases in the `FOR UPDATE OF` clause.
> Starting from v8.5.6, TiDB supports using table aliases in the `FOR UPDATE OF` clause. To maintain backward compatibility, you can still reference the base table name when an alias is defined, but this triggers a warning that recommends using the explicit alias. When a query involves multiple tables with the same name across different databases (for example, `FROM db1.t, db2.t FOR UPDATE OF t`), TiDB now matches the target table from left to right based on the order in the `FROM` clause, rather than the current database context. To avoid ambiguity, it is recommended that you specify the database name or use aliases in the `FOR UPDATE OF` clause.
References
  1. The documentation should be written in the second person ('you') when addressing users. (link)
  2. The documentation should avoid unnecessary words and repetition for conciseness. (link)
  3. The documentation should avoid overuse of passive voice. (link)


## Examples

### SELECT
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