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ordered_merge improvements #1870
(unless something else was meant here). This has been in for a while.
@jreback Unlike the pd.ordered_merge(), the kdb aj() only keeps the rows from the left-hand table.
I.e., as with a regular left-join, the table doesn't get more rows; it just appends columns from the right-hand table.
Actually, it's very similar to a left-join, but instead of searching for equal keys, it searches for the greatest key from the right-hand table that is less-than-or-equal-to the key from the left-hand table. This is exactly what the asof function does in pandas, so we're part of the way there already.