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    <p>This is an application of windows functions (called analytic functions in Oracle).</p> <p>Your goal is to assign a "block number" to each sequence of stops. That is, all stops in a sequence (for a vehicle) will have the same block number, and this will be different from all other sequences of stops.</p> <p>Here is a way to assign the block number:</p> <ol> <li>Create a speed flag that says 1 when speed > 0 and 0 when speed = 0.</li> <li>Enumerate all the records where the speed flag = 1. These are "blocks".</li> <li>Do a self join to put each flag = 0 in a block (this requires grouping and taking the max blocknum).</li> <li>Summarize by duration or however you want.</li> </ol> <p>The following code is a sketch of what I mean. It won't solve your problem, because you are not clear about how to handle day breaks, what information you want to summarize, and it has an off-by-1 error (in each sequence of stops it includes the previous non-stop, if any).</p> <pre><code>with vd as ( select vd.*, (case when SpeedFlag = 1 then ROW_NUMBER() over (partition by id, SpeedFlag) end) as blocknum from ( select vd.*, (case when speed = 0 then 0 else 1 end) as SpeedFlag from vehicaldata vd ) vd ) select id, blocknum, COUNT(*) as numrecs, SUM(duration) as duration from ( select vd.id, vd.rtime, vd.duration, MAX(vdprev.blocknum) as blocknum from vd left outer join vd vdprev on vd.id = vdprev.id and vd.rtime &gt; vdprev.rtime group by vd.id, vd.rtime, vd.duration ) vd group by id, blocknum </code></pre>
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