Support converting JSON to STRUCT · StarRocks/starrocks#43101

(12 留言) (2 反應) (1 負責人)Java (5,717 star) (1,246 fork)batch import

good first issuetype/feature-requestversion:3.2.9version:3.3.0version:3.4

描述

Is your feature request related to a problem? Please describe.

STRUCT type is more performant that JSON in terms of query, but which use the fixed schema and annoying to construct.

If it's possible to convert JSON to STRUCT directly, like to_struct(JSON), it can be much easier to use.

Describe the solution you'd like

Use a function to convert JSON to STRUCT:
- Example: select to_struct(parse_json("{"a": 1}"))
- Difficulty: cannot inference the schema of struct before parsing the JSON
Specify the STRUCT schema and convert:
- Example: select to_struct<a int, b int>(parse_json("a": 1, "b": 2))
- Difficulty: not easy to use

Describe alternatives you've considered

Additional context

技術棧: javasql
領域: backenddatabase
議題類型: feature
難度: 4
預計時間: over 1 week
活動狀態: blocked
清晰度: mostly clear
前置要求: Familiarity with StarRocks codebaseKnowledge of JSON and STRUCT typesUnderstanding of SQL function registration
新手友善度: 15
研究方向: Examine the three linked PRs (#47233, #46448, #45406) to understand previous work on type conversions in StarRocks. Review the issue comments for any maintainer suggestions on the preferred approach. Investigate the SQL parser and type system in the StarRocks codebase to determine how to register a new function like `to struct`. Consider the schema inference challenge mentioned in the issue.