apache / apache/datafusion-sqlparser-rs

Support `COLUMNS(* EXLCUDE(col1, col2))` syntax

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Dominant language
Rust
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Merged PRs (30d)
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Description

DuckDB supports excluding columns via this syntax:

```
SELECT COLUMNS(* EXCLUDE(col1, col2)) FROM tbl
```

Currently this format gives a syntax error:

```
Parse error: sql parser error: Expected: ), found: EXCLUDE at Line: 1, Column: 18
```

More details at: https://duckdb.org/docs/stable/sql/expressions/star.html#columns-expression

Note that other modifiers beyond `EXCLUDE` are supported, such as `REPLACE`, `RENAME`, `LIKE` etc, see the syntax diagram at https://duckdb.org/docs/stable/sql/query_syntax/select.html#syntax (click `star-options` on the digram to expand).

This highly suggests that the general solution for this would be to add a new `Expr::Columns` expression enum with parsing logic somewhat similiar to `Expr::MatchAgainst`, and then add logic in `parse_select_item` to support returning a `SelectItem::UnnamedExpr(Expr::Columns)`.

Contributor guide

No contributing guide indexed for this repository

Research direction

Start at parse_select_item and compare the parsing path for Expr::MatchAgainst. Add support for an Expr::Columns expression returned as SelectItem::UnnamedExpr(Expr::Columns), then verify the documented COLUMNS(* EXCLUDE(...)) form and the listed REPLACE, RENAME, and LIKE modifiers parse successfully.

Written by the indexing model from the issue text.

Assessment

Tech stack
rust, sql
Domain
compilers
Issue type
Feature
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
45/100

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