Feature Request: support derivation as LHS for filter, post-filter, aggregation

[akphi]

Similar requests

• I have searched and found no existing similar requests

Context and Motivation

We want to support use cases like the following:

|model::Person.all()->filter(
  p|$p.firstName + $p.lastName == 'John Doe'
)->project(
  [
    x|$x.firstName,
    x|$x.lastName
  ],
  [
    'First Name',
    'Last Name'
  ]
)

Currently, this type of query triggers the unsupported view on the user which is very user-friendly.

What problems are you trying to solve?

This is similar to #254, but this time we want to do it for filter, post-filter, and aggregation

Describe the solution you would like to see implemented

This differs from #254 a bit since a filter is not a list like projections, but a tree structure. As such, some special handling must be in place. For example:

• ? Add a new method to QueryBuilderFilterOperator
• Create another visitor that extends V1_ValueSpecificationBuilder visitor that handles the building within the filter function in a special way, because unlike projection, filter is a tree structure.
• When we introduce derivation for filter, we would need to support something similar to add functions explorer panel in query builder #888
• We need to take care of the case in Feature request: Post Filter in Query Editor #839 where after DnD to create the column, the user change the projection derivation changing the return type, do we need to reevaluate to check if post-filter condition still valid or not

Describe alternatives you have considered

N/A

Documentation, Design, Adoption, Migration Strategy

No response

Contribution

• I would like to work on this feature

[akphi]

@YannanGao-gs After discussing with @MauricioUyaguari we decide to rescope this to include handling logic for post-filter and aggregation as well. This will require more in-depth discussion. So for now I'll unassign you.