[ARROW-9911] [Rust][DataFusion] SELECT <expression> with no FROM clause should produce a single row of output

• Type: Improvement
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Fix Version/s: 3.0.0
• Component/s: Rust, Rust - DataFusion
• Labels: beginner pull-request-available
• External issue URL: https://github.com/apache/arrow/issues/25943
• Assignee: Ruihang Xia
• Reporter: Andrew Lamb
• Created: 03/Sep/20 20:16
• Updated: 11/Jan/23 08:09
• Resolved: 15/Nov/20 12:45

Description

This is somewhat of a special case, but it is useful for demonstration / testing expressions.

A select expression with no where clause, such as "select 1" should produce a single row. Today datafusion accepts the query but produces no rows.

Actual output:

arrow/rust$ cargo run --release  --bin datafusion-cli 
    Finished release [optimized] target(s) in 0.25s
     Running `target/release/datafusion-cli`
> select 1 ;
0 rows in set. Query took 0 seconds.

Expected output is a single row, with the value 1. Here is an example using SQLLite :

$ sqlite3 
SQLite version 3.28.0 2019-04-15 14:49:49
Enter ".help" for usage hints.
Connected to a transient in-memory database.
Use ".open FILENAME" to reopen on a persistent database.
sqlite> select 1;
1
sqlite> 

Issue Links

• links to: GitHub Pull Request #8662