yzeng1618 opened a new pull request, #11971:
URL: https://github.com/apache/seatunnel/pull/11971
### Purpose of this pull request
Fix #11969 (same root cause as the historical report #8329).
When a JDBC source table is defined by `query` only, the schema is derived
from JDBC `ResultSetMetaData`, which carries no column/table comments,
constraint keys or partition keys. Sinks that auto-create tables (Doris,
StarRocks, MySQL, ...) therefore create tables without any comments.
This PR resolves the underlying physical table from the query result
metadata when the query maps to a single table (e.g. `SELECT * FROM db.table`),
and merges the missing metadata (column/table comments, primary key, constraint
keys, partition keys, table options) into the query-derived table by reusing
the existing `mergeCatalogTable` logic — the same behavior as configuring
`table_path` together with `query`.
The merge is defensive:
- Applied in both the catalog path and the no-catalog fallback path, only
when the underlying table can be resolved and exists with a non-empty schema;
- Columns renamed or transformed in the query keep the query-derived
definition (`mergeCatalogTable` guards by column name + SqlType);
- Any failure loading the underlying table falls back to the current
query-derived behavior.
### Does this PR introduce _any_ user-facing change?
Yes. When a JDBC source uses `query` without `table_path` and the query maps
to a single existing table, the produced catalog table now carries the comments
/ primary key / constraint keys / partition keys of that table, so sinks with
auto table creation preserve them; previously they were silently lost. The Jdbc
source documentation (en/zh) is updated accordingly.
### How was this patch tested?
- New unit tests in `JdbcCatalogUtilsTest` covering: resolvable single-table
query (metadata merged), unresolvable table name, database/schema missing,
underlying table not existing, underlying table with empty schema, and loader
failure fallback.
- Extended `JdbcMysqlTableOptionsIT`, whose job config is exactly a
query-only MySQL-to-MySQL auto-create scenario: the source table now declares
column comments and a table comment, and the IT asserts they are present in
`SHOW CREATE TABLE` of the auto-created sink table.
### Check list
* [ ] If any new Jar binary package adding in your PR, please add License
Notice according
[New License
Guide](https://github.com/apache/seatunnel/blob/dev/docs/en/developer/new-license.md)
* [x] If necessary, please update the documentation to describe the new
feature. https://github.com/apache/seatunnel/tree/dev/docs
* [ ] If necessary, please update `incompatible-changes.md` to describe the
incompatibility caused by this PR.
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