On 15 Sep 2016, at 9:46pm, David Raymond <david.raym...@tomtom.com> wrote:
> The idea is to find the closest date that matches that couldn't be matched to > another record. [snip] > Can this join be done in SQL? I wouldn't even try to do it in any SQL engine. It would be ridiculously difficult to debug. Even "the closest date that matches that couldn't be matched to another record" by itself requires processing every row of a table using a metric you haven't defined. If I did do it I'd use multiple parses. One parse to work out the matching key values for each table and store them in another column of the table, the final parse to do the LEFT JOIN query. But your question is phrased not in terms of set operations SQL implements but in terms of a standard procedural programming language, so perhaps you should use one. Sooner or later you're going to have to do some programming. Simon. _______________________________________________ sqlite-users mailing list sqlite-users@mailinglists.sqlite.org http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users
