On 7 March 2016 at 14:18, I wrote:
> That assumes that I've not completely misunderstood, of course :)
Always a dangerous assumption, I'm rapidly learning.
The very next section:
Constraints on columns to the right of these columns are checked
in the index, so they save visits to the table proper, but they do not
reduce the portion of the index that has to be scanned.
So it seems that it should in fact be usable after all. So I'm still
stumped as to why the (scdate,sc_id) index isn't used :(
Geoff
