Use backquote for table and column names

[DongLiang-0]

Previously, columns and tables in SQL used double quotes, but in doris syntax, columns and tables should use back quotes, otherwise they will be recognized as a string. This change is applicable to both clickhouse and doris

select "col1" from tab1 -> select `col1` from `tab1`

[mieciu]

Thanks a lot for your contribution!

I think that instead of swapping " with `, this should be configurable, depending on the backend connector. While this syntax is fine with ClickHouse/Hydrolix, it's non supported in something like Postgres.

Therefore, there should be no need to change any of the existing test cases.

How I would see this change moving forward

We have this oversimplification of model.LiteralExpr being used for column/table names and aliases. This is the moment where we need to refactor that.

We need to create model.IdentifierExpr for our query AST which should replace model.LiteralExpr whenever referring to column/table name. Then, when rendering to SQL we should transform it accordingly to the database backend we're connected to. ClickHouse/Hydrolix -> let's stick to ". For Doris, we can use "`".

In that way, we won't have to change any of the existing tests, make adding different data sources easier and there's way less risk of introducing regression to the codebase.

[DongLiang-0]

Thanks a lot for your contribution!

I think that instead of swapping " with `, this should be configurable, depending on the backend connector. While this syntax is fine with ClickHouse/Hydrolix, it's non supported in something like Postgres.

Therefore, there should be no need to change any of the existing test cases.

How I would see this change moving forward

We have this oversimplification of model.LiteralExpr being used for column/table names and aliases. This is the moment where we need to refactor that.

We need to create model.IdentifierExpr for our query AST which should replace model.LiteralExpr whenever referring to column/table name. Then, when rendering to SQL we should transform it accordingly to the database backend we're connected to. ClickHouse/Hydrolix -> let's stick to ". For Doris, we can use "`".

In that way, we won't have to change any of the existing tests, make adding different data sources easier and there's way less risk of introducing regression to the codebase.

very good plan

[DongLiang-0]

I'll close this PR.