Key matching conditions

• Equality condition: so called ‘equi joins’.
  • You will use this most of the time.
  • All others are sometimes called ‘non-equi joins’
• Inequality conditions:
  • inequality joins: join_by(id < id)
  • rolling joins (only closest): join_by(closest(id < id))
  • overlap joins: to set interval conditions
    • between(x, y_lower, y_upper) is short for x >= y_lower, x <= y_upper
    • within(x_lower, x_upper, y_lower, y_upper) is short for x_lower >= y_lower, x_upper <= y_upper
    • overlaps(x_lower, x_upper, y_lower, y_upper) is short for x_lower <= y_upper, x_upper >= y_lower
• No conditions: cross joins. Use separate function cross_join().