Trailing comma output misleading error message

[alexandreyc]

Describe the bug

Putting a trailing comma after the last column/expression within a select statement produces a misleading error message.

To Reproduce

When running the following:

create table my_table as (
    select 'Alice' as name, 42 as age
    union all
    select 'Bob' as name, 1337 as age
);

select
    name,
    age,
from
    my_table

We got the following error message:

Schema error: No field named name.

Expected behavior

Either:

• Accepting trailing comma
• Have an informative error message

Additional context

It took me a while to figure out the issue so I though that it might be helpful to improve on this.

[jonahgao]

In this case, sqlparser-rs interprets from as a column name, and my_table is recognized as the alias of the from column. Not sure whether we need to solve this problem in sqlparser-rs or in DataFusion. In some databases, from as a keyword cannot be used as a column name.

[alamb]

Thanks Looks lik

looks like there is a PR upstream to fix this: https://github.com/sqlparser-rs/sqlparser-rs/pull/1212 - I'll try and review it shortly

[MohamedAbdeen21]

Thanks for the issue @alexandreyc.

https://github.com/sqlparser-rs/sqlparser-rs/pull/1212 is merged.

The new error message is:

Error during parsing: ParserError("Expected an expression, found: from at Line: 11, Column 5")

However, it will be several weeks till it arrives to DF, since we'll have to wait for the new release of sqlparser, sqlparser version upgrade in DF, and then the new release of DF.