Determine future of FROM DML statements

[johnedquinn]

Relevant Issue/Bug

• Adds DML (INSERT, DELETE, UPDATE, UPSERT, REPLACE) #1666

Requested Solution/Feature

• In Adds DML (INSERT, DELETE, UPDATE, UPSERT, REPLACE) #1666, the FROM DML statements were removed intentionally due to the lack of an RFC and an active customer.
• There were also issues with parsing with this. We accidentally allowed for FROM to precede any DML statement, such as DELETE, which is not supported by QLDB. The syntactical feature has been removed until its semantics have been formalized by the PartiQL Team.

Additional Context

• FROM DML is used by the end-of-support QLDB. See the above link for the documentation.

DoD (Definition of Done)

• Determine whether FROM (INSERT, REMOVE, SET) will be in the official PartiQL Language.
  • Note: If we do add it, we should have dedicated AST nodes to disambiguate syntax from semantics. AKA a FromInsert, FromRemove, FromSet.