Never mind. Noob mistake. My tally table was too small.

Eddie, this looks to be exactly what I'm looking for -- when I run your query as written, though, I get no results returned. Are you missing a step in...

Thanks, Geoff. That's what I'm exploring now -- setting up a months table to join against. I had wanted to avoid that, but I'm not certain that I had a...

Thanks Jimbo.

Here's the basic table: it's for calculating a meter's usage over time.

meterid (varchar(12)) read date (datetime) ...

That's what I figured. I just wanted to make sure I wasn't talking out of my uneducated half.

There are two other nonclustered indexes, but they are not being reindexed here, so I'm not sure they'd have a bearing anyway.

Looks to be between 700K rows per insert.

Raw data is loaded into a table from CSV (I'm guessing, I'm not involved in how the data gets to us). The...