Convert ApproxPercentileCont and `ApproxPercentileContWithWeight to UDAF

[goldmedal]

Is your feature request related to a problem or challenge?

Similar to #10838 and others #8708
However, there're some challenge to convert ApproxPercentileCont.
I discussed with @jayzhan211 in #10838 (comment)

Describe the solution you'd like

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Describe alternatives you've considered

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Additional context

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[goldmedal]

take

[goldmedal]

Hi @jayzhan211,

Continuing from our previous discussion in #10838 (comment), I believe there are still some issues.

We create AccumulatorArgs in
https://github.com/apache/datafusion/blob/main/datafusion/physical-expr-common/src/aggregate/mod.rs#L287.

However, AggregateFunctionExpr only takes args that are PhysicalExpr. I think AccumulatorArgs is a logical plan struct that should be placed in datafusion-expr. It can't access PhysicalExpr.

Curiously, is it possible to convert PhysicalExpr back to Expr?
If not, I plan to pass the original Expr to AggregateFunctionExpr (just like sort_exprs: Vec<Expr>), then pass it to AccumulatorArgs.

Does this make sense? What do you think?
Thanks

[jayzhan211]

is it possible to convert PhysicalExpr back to Expr?

I think it is possible, but in this case, we can just pass the Expr: Vec<Expr> to AggregateFunctionExpr like SortExpr is