Lineage Analysis Incorrectly Captures Source Tables for UNION Query

[predator4ann]

Description
The data lineage analysis fails to capture all source columns when processing UNION ALL operations. Specifically, lineage information for tb2 is missing in the following query scenario.

SQL to Reproduce

CREATE TABLE memory.test.tb1 (id VARCHAR);

CREATE TABLE memory.test.tb2 (id VARCHAR);

SELECT id FROM (
    SELECT id FROM tb1
    UNION ALL
    SELECT id FROM tb2
) t;

Observed Behavior

{
  "OutputColumn": {
    "column": "id (varchar)",
    "sourceColumns": [
      {"tableName": "memory.test.tb1", "columnName": "id"}
    ]
  }
}

Expected Behavior

{
  "OutputColumn": {
    "column": "id (varchar)",
    "sourceColumns": [
      {"tableName": "memory.test.tb1", "columnName": "id"},
      {"tableName": "memory.test.tb2", "columnName": "id"}
    ]
  }
}