feature_03_derived_table

Feature: Derived Table

파생된 테이블과 관련된 기능입니다.

Supported Language

✔ = 지원하는 기능
❌ = 지원하지 않는 기능
⚠ = 지원 예정

Feature	MySql	PostgreSql	JSql	Oracle	SqlServer
Derived Table (w/ Alias)	✔	✔	✔	✔	✔
Derived Table (w/o Alias)	❌	❌	✔	✔	❌

Case 1. Derived Table with Alias

Example Query

SELECT * FROM (SELECT * FROM sample_table) AS alias

Database

---

Database.Table = sample_db.sample_table

Columns = sample_column1, sample_column2

---

Expected QSI Tree

• IQsiDerivedTableNode
  • Columns
    • IQsiColumnsDeclarationNode
      • Columns
        • IQsiAllColumnNode
  • Source
    • IQsiDerivedTableNode
      • Columns
        • IQsiColumnsDeclarationNode
          • Columns
            • IQsiAllColumnNode
      • Source
        • IQsiDerivedTableNode
          • Columns
            • IQsiColumnsDeclarationNode
              • Columns
                • IQsiAllColumnNode
          • Source
            • IQsiTableAccessNode
              • Identifier = sample_table
      • Alias
        • IQsiAliasNode
          • Name = alias

Analyze Result

• sample_column1 (derived)

  • sample_column1 (derived: alias)
    • sample_column1 (table: sample_db.sample_table)
      • Reference : sample_db.sample_table

• sample_column2 (derived)

  • sample_column2 (derived: alias)
    • sample_column2 (table: sample_db.sample_table)
      • Reference : sample_db.sample_table

위와 같은 쿼리 결과에서 SELECT 절 이후 SELECT * FROM sample_table 서브 쿼리를 DerivedTable로 처리해 결과를 추적합니다. 이때 해당 서브쿼리는 별칭이 적용되었으므로 alias라는 별칭으로 추적됩니다.

Case 2. Derived Table without Alias

Example Query

SELECT * FROM (SELECT * FROM sample_table)

Database

Database.Table = sample_db.sample_table

Columns = sample_column1, sample_column2

Expected QSI Tree

• IQsiDerivedTableNode
  • Columns
    • IQsiColumnsDeclarationNode
      • Columns
        • IQsiAllColumnNode
  • Source
    • IQsiDerivedTableNode
      • Columns
        • IQsiColumnsDeclarationNode
          • Columns
            • IQsiAllColumnNode
      • Source
        • IQsiTableAccessNode
          • Identifier = SAMPLE_TABLE

Analyze Result

• sample_column1 (derived)

  • sample_column1 (derived)
    • sample_column1 (table: sample_db.sample_table)
      • Reference : sample_db.sample_table

• sample_column2 (derived)

  • sample_column2 (derived)
    • sample_column2 (table: sample_db.sample_table)
      • Reference : sample_db.sample_table

위와 같은 쿼리 결과에서 SELECT 절 이후 SELECT * FROM sample_table 서브 쿼리를 DerivedTable로 처리해 결과를 추적합니다.