Got it:
SELECT state1, timestamp
FROM (SELECT state1, timestamp, lag(state1) OVER (ORDER BY timestamp) FROM test) as foo
WHERE state1 != lag OR lag IS NULL
ORDER BY timestamp;
state1 | timestamp
--------+----------------------------
1 | now() - interval '12 hours'
2 | now() - interval '9 hours'
1 | now() - interval '8 hours'
Without lag IS NULL I miss the first row.
On Thu, May 27, 2010 at 11:44 AM, Nikolas Everett <nik9000@xxxxxxxxx> wrote:
The 10 and 11 hour interval are being skipped because I'm only interested in the transitions of state 1. State 1 only transitioned three times at now - 12, now - 9 and now - 8.The table has both transitions in it because I frequently care about them both together. I just don't in this case.
On Thu, May 27, 2010 at 12:36 PM, Justin Graf <justin@xxxxxxxxxxxx> wrote:On 5/27/2010 9:45 AM, Nikolas Everett wrote:Have a question what makes these values different other than the timestamp???Sorry. Here is the setup:CREATE TABLE test (id BIGSERIAL PRIMARY KEY, state1 INT NOT NULL, state2 INT NOT NULL, timestamp TIMESTAMP);INSERT INTO test (state1, state2, timestamp) VALUES (1, 1, now() - interval '12 hours');INSERT INTO test (state1, state2, timestamp) VALUES (1, 2, now() - interval '11 hours');INSERT INTO test (state1, state2, timestamp) VALUES (1, 1, now() - interval '10 hours');INSERT INTO test (state1, state2, timestamp) VALUES (2, 1, now() - interval '9 hours');INSERT INTO test (state1, state2, timestamp) VALUES (1, 1, now() - interval '8 hours');
I want to write a query that spits out:state1 | timestamp--------+----------------------------1 | now() - interval '12 hours'2 | now() - interval '9 hours'1 | now() - interval '8 hours'
1, 1, now() - interval '12 hours'
1, 1, now() - interval '10 hours'The reason i ask, is because you show 1, 1, now() - interval '8 hours' in the desired output. What logic keeps the 8 hour and 12 hour but not the 10hour interval???
Its kinda hard to understand why the 10hour interval is being skipped???
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