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substrait-io / substrait

A cross platform way to express data transformation, relational algebra, standardized record expression and plans.
https://substrait.io
Apache License 2.0
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feat: add current_date and current_timestamp functions #548

Open richtia opened 1 year ago

richtia commented 1 year ago

PR to add current_date and current_timestamp functions'

jacques-n commented 9 months ago

I made some comments in the last sync. Basically, I don't think the "batch" mode of these is actually a function. It would be what I would call a contextual function. The function needs to evaluate and is determinant given the same context values. Context values are things like the time when the query ran, the timezone of the user, the currently selected database, etc. These context functions could be a new unique expression type or could be an extended version of what we talked before for variables in prepared statements (since they are basically pointers to external variables).

For the "STREAM" case, I think this is fine. However, I think we should probably use a different name to avoid confusion from people coming from the SQL world, where there is always the "BATCH" behavior.