Michael,
>SELECT t1.id, t1.version, t1.value
>FROM data t1
>LEFT JOIN data t2 ON t1.id=t2.id AND t1.version < t2.version
>WHERE t2.id IS NULL;
>I had almost the same problem and I found this solution very smart...
>even smarter than I can understand :)
>Can someone explain to me why/how this query works ?
A two-step:
1. The left join creates a logical table with t1.ids on the left, and on
the right ...
(a) matching t2.ids, when t1.version<t2.version, or
(b) nulls when t1.version>=t2.version.
2. The where clause removes (a), leaving only the t1.ids for which
there's no greater version.
PB
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