Samyak2 opened a new pull request, #20628:
URL: https://github.com/apache/datafusion/pull/20628

   ## Which issue does this PR close?
   
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   Needed in https://github.com/datafusion-contrib/datafusion-variant/issues/26
   
   ## Rationale for this change
   
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   - `sqlparser-rs` currently exposes the colon operator (`:`) as a special 
`JsonAccess` expression. So it fails in datafusion's parsing before an 
`ExprPlanner` is even invoked.
   
   ## What changes are included in this PR?
   
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   - Fixes the above problem by converting `JsonAccess` to a normal binary 
expr, on which the `ExprPlanner` is invoked and custom parsing can be done.
   
   ## Are these changes tested?
   
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   not yet
   
   ## Are there any user-facing changes?
   
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   No. Datafusion still does not support the colon operator.
   
   ## Alternatives considered
   
   I have arrived at this solution iteratively to solve 
https://github.com/datafusion-contrib/datafusion-variant/issues/26. Some 
alternatives I considered (but NOT IMPLEMENTED):
   - Add a new `Operator::Colon` variant instead of `BinaryOperator::Custom`. 
This will make more sense to do if datafusion plans on supporting the colon 
operator on other data types (like json strings).
   - Add a new `Expr::JsonAccess` instead of re-using `BinaryExpr`. Alongside 
this, we could also introduce datafusion's version of a `JsonPath` struct. 
`Expr::JsonAccess` could also contain the optional cast that usually comes 
after it (like in `col_a:field_b::int`). The cast might be needed for 
performance optimizations. This is a much bigger change, so I have not done it.
   
   If either of these make sense to do at this time, please let me know and I 
will do theose changes.
   


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