Application of `WHERE` clause and renaming columns

[uberroot4]

Hello, I've encountered your project and tried to implement some (imo) missing columns for some types. When it comes to the diffs table, I am missing a reference to where the diff was made to. Checking the code I found it and decided to simply add it to the possible columns:

1. Extending the TABLES_FIELDS_TYPES by map.insert("diff_to", DataType::Text);
2. Extending the TABLES_FIELDS_NAMES ("diffs") by "diff_to"

3. Modifying the git_data_provider by:

   if field_name == "diff_to" {
   let diff_to_cid = commit_info
       .parent_ids()
       .next()
       .map(|p| p.object().unwrap().id.to_string());
   
   match diff_to_cid {
       Some(value) => values.push(Value::Text(value)),
       None => values.push(Value::Text("".to_string())),
   };
   
   continue;
   }

4. Pretty straight forward all together, also it works when I execute the query like this:

   SELECT commit_id AS from_,diff_to AS to_,name FROM diffs LIMIT 10;

5. However, when I execute it like this (i.e. renaming the diff_to while I'm having it in the WHERE clause, it raises an error: "Invalid column name diff_to". When i use WHERE to_ IS NULL then it wirks fine.

   SELECT commit_id AS from_,diff_to AS to_,name AS b FROM diffs WHERE diff_to IS NULL LIMIT 10;

Expected behavior As far as I am aware of SQL, renaming a column and using it in a WHERE clause is exact the opposite as in GQL. So I think the renamig part in the rust Code should be applied after the consolidation of all columns.

Another remark When investigating the problem (at first I thought the problem lies somewhere else), I encountered that the LIMIT X clause is applied after the SELECT statement -- respectively I just tried a simple println for debugging. For the sake of resource management, shouldn't it be applied before? Meaning that GQL could abort the revwalk section after X iterations?

GQL:

• Version 0.16.0

Best, Manuel

[AmrDeveloper]

Hello @uberroot4,

The first point is valid and should be improved to work exactly like SQL

The Limit point is on TODO but it will require a more advanced QueryPlanner and Optimizer to make it work perfect

[AmrDeveloper]

Hello @uberroot4,

This issue fixed on 0.22.0

You can now run select commit_count as cc from branches where commit_count > 1

[AmrDeveloper]

https://github.com/AmrDeveloper/GQL/releases/tag/0.22.0