19.5.3 Rolling joins - parties example

[brtkl]

"And for each employee we want to find the first party date that comes after (or on) their birthday. We can express that with a rolling join:"

employees |> 
  left_join(parties, join_by(closest(birthday >= party)))

The sentence should rather be: "And for each employee we want to find the last party date that comes before (or on) their birthday. We can express that with a rolling join:"

Alternatively, the code could be updated as follows

employees |> 
  left_join(parties, join_by(closest(birthday <= party)))

if we want parties after birthdays as mentioned in the original sentence

[florisvdh]

I prepared PR #1645 to fix this issue.

Alternatively, the code could be updated as follows

employees |> 
  left_join(parties, join_by(closest(birthday <= party)))

if we want parties after birthdays as mentioned in the original sentence

True, but I haven't followed that since it would render the narrative and examples that come next obsolete.