ORDER BY support

[willy610]

Hej,

Sorry for all issues. Not complaining. Love the SQL and in Rust!

But browsing into my swedish testdabase on recipes and it's categories
the output is not ordered on column 2.

(We have the same sort order in Swedish as in any Latin-1 countries)

"select * from category where categoryid > 50 order by 2;"
53 "Fläskkött" ""
54 "Vegetarisk" ""
55 "Pastej" ""
56 "Gratäng" ""
57 "Finskt" ""
58 "Kassler" ""

[panarch]

That's welcome at all, and I'm so pleased about your reportings.

Let's simply rename this issue to "ORDER BY support"

ORDER BY is a type of query which may work best with index, but it still requires to work without index, too.
This issue is implementing ORDER BY without considering indexing stuff.

[willy610]

ORDER BY is an outer cover only useful for the presentation of result. Look into the AST Struct sqlparser::ast::Query A kind of sibling limit

One can assume that the ordering mostly is on a subsets due to joins and where.

The location of an order by is probably in executor/execute.rs and after the select_with_labels

I did an implementation of order by in the benchmark https://github.com/willy610/abcsql.git

(Besides ORDER BY it holds a lot functionality)

It's very similar when using gluesql to take care of requests pattern

let storage = get_storage(how);
let mut glue = Glue::new(storage);
for query in parse(&one_query).unwrap() {
    match &glue.execute(&query).unwrap() {
        Select { labels, rows } => {
           let rows = orderby(labels.to_vec(), rows.to_vec(), &order_by);
           ...

The order by is like

1. Compile the AST order_by into columnnumber and ask/dsc
2. Insert each row in a BinaryHeap with Ord implementation using the compiled order_by
3. Retrieve the rows and return them

I think the orderby.rs can be adapted quit easily into executor/execute.rs

[KyGost]

@willy610

I did an implementation of order by in the benchmark https://github.com/willy610/abcsql.git

Did you do it on the GlueSQL side?
If so, could you share the code or put up a PR?

[willy610]

Hello If you want to lock at how I did the ORDER BY Look into the source of https://github.com/willy610/abcsql.git You will find it in src/abcsql/applic_folder/orderby.rs ( called from src/abcsql/applic_folder/go_exec.rs ) Hope this will contribute to some implementation Kindly willy

…

On 2021-02-27, at 12:23, Kyran Gostelow ***@***.***> wrote: @willy610 I did an implementation of order by in the benchmark https://github.com/willy610/abcsql.git Did you do it on the GlueSQL side? If so, could you share the code or put up a PR? — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub, or unsubscribe.

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[KyGost]

@willy610
Thanks :-)