leaves12138 commented on code in PR #7976: URL: https://github.com/apache/paimon/pull/7976#discussion_r3307898474
########## docs/docs/spark/sql-write.md: ########## @@ -221,6 +221,20 @@ WHEN NOT MATCHED THEN INSERT * -- when not matched, insert this row without any transformation; ``` +### Column Alignment + +Assignments are aligned to the target by column name, and unmentioned target columns are filled with NULL. + +`INSERT *` / `UPDATE SET *` expand against the target columns: + +- Source columns missing from the target are rejected by default. Enable `spark.paimon.write.merge-schema` to keep them and evolve the table schema at write time (see [Write Merge Schema](#write-merge-schema)). Review Comment: This section does not seem to match the implementation and the new tests. For top-level source-only columns under `UPDATE SET *` / `INSERT *`, strict mode currently drops them (for example `source extra columns silently dropped under star expansion (mergeSchema=false)`), while `merge-schema=true` evolves the target schema. Conversely, for target-only columns missing from the source, strict `UPDATE SET *` / `INSERT *` throws, and only merge-schema mode preserves the target value for `UPDATE SET *` or fills default/NULL for `INSERT *`. Could you adjust these bullets to describe those four cases explicitly? -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
