Add or transform columns
Details
Supported expression types: arithmetic (+, -, *, /, %%),
comparison, boolean, is.na(), nchar(), substr(), grepl() (fixed
match only). Window functions (row_number(), rank(), dense_rank(),
lag(), lead(), cumsum(), cummean(), cummin(), cummax()) are
detected automatically and routed to a dedicated window node.
When grouped, window functions respect partition boundaries.
This is a streaming operation for regular expressions; window functions materialize all rows within each partition.