planner/core: the order by with default field not parsed (#11210)

[gaoxingliang]

What problem does this PR solve?

Fix #11210
when order by with default(colName) is not resolved and got unknown column

What is changed and how it works?

parse the column name expr in the order by resolver.

Check List

Tests

• Unit test -- added and passed

[sre-bot]

Hi contributor, thanks for your PR.

This patch needs to be approved by someone of admins. They should reply with "/ok-to-test" to accept this PR for running test automatically.

[gaoxingliang]

Need more time to fix UTs

[zz-jason]

@gaoxingliang friendly ping, any update?

[gaoxingliang]

@gaoxingliang friendly ping, any update?

the progress is not good. I think I missed something when I try to parse the ColumnName so many cases need to be considered (similar with the ColumnNameExpr, but I don't understand the difference). I think I need to close this PR temp now and do more checks.

[eurekaka]

Can we check if the column has default value definition in expression rewriting of buildSort and report error (if no definition) or replace the ByItem to a constant?

[zz-jason]

@gaoxingliang friendly ping, any update?

[gaoxingliang]

Can we check if the column has default value definition in expression rewriting of buildSort and report error (if no definition) or replace the ByItem to a constant?

Hi @eurekaka , it will not working. I test and found the schema information is not correct when we calling the plan.schema in buildSort and try to remapped in the itemTransformer

[eurekaka]

@gaoxingliang Sorry I didn't get your point. IMHO, theoretically, we can make the transformation when resolving the ORDER BY clause.

[gaoxingliang]

Hi @eurekaka below is more details about this issue.
the problem occur when the default(x) is not added into the plan p.Schema() at logical_plan_builder.go#buildSort
So I try to find where the schema select fields are added with comparison with another func like length(x)
I found it's added in the havingWindowAndOrderbyExprResolver with case ColumnNameExpr at here for length function.
but for default function, it's a ColumnName instead of a ColumnNameExpr which I think this is what parser done. I don't get the difference.

for your suggestion, the [transformer] (https://github.com/pingcap/tidb/blob/release-3.0/planner/core/logical_plan_builder.go#L2132) happened after the error occur. so I don't think that will fix this problem.

[zz-jason]

Hi @gaoxingliang, friendly ping, any update?

[sre-bot]

@gaoxingliang, please update your pull request.

[sre-bot]

@gaoxingliang, please update your pull request.

[sre-bot]

@gaoxingliang PR closed due to no update for a long time. Feel free to reopen it anytime.