I have a table, where events of certain objects are listed.
There are two events: "movement" and "load". They can start and end, and these events are listed with timestamps when they happened.
Now i want to calculate the following three numbers:
I have created a sqlfiddle for the problem here:
Try this
For load answer will be 630 not 690
For the 1st and second case
SELect max(timestamp) - min(timestamp), LEFT(event, LOCATE(' ', event))
FROM table1
group by id, LEFT(event, LOCATE(' ', event));
For 3 rd case
SELect max(timestamp) - min(timestamp), id
FROM table1
group by id;
The first two columns compute the differences between corresponding end
/ start
events. (Summation is commutative, so we don't need to actually match corresponding events.)
The third colum searches for movement start
events for which the preceding load
event is a load start
event, and for movement end
events for which the following load
event is a load end
event.
SELECT (SELECT SUM(timestamp)
FROM Table1
WHERE event = 'movement end') -
(SELECT SUM(timestamp)
FROM Table1
WHERE event = 'movement start') AS all_movement,
(SELECT SUM(timestamp)
FROM Table1
WHERE event = 'load end') -
(SELECT SUM(timestamp)
FROM Table1
WHERE event = 'load start') AS all_load,
(SELECT SUM(timestamp)
FROM Table1 a
WHERE event = 'movement end' AND
(SELECT event
FROM Table1 b
WHERE timestamp = (SELECT min(timestamp)
FROM Table1 c
WHERE c.timestamp >= a.timestamp
AND c.event LIKE 'load %')
) = 'load end') -
(SELECT SUM(timestamp)
FROM Table1 a
WHERE event = 'movement start' AND
(SELECT event
FROM Table1 b
WHERE timestamp = (SELECT max(timestamp)
FROM Table1 c
WHERE c.timestamp <= a.timestamp
AND c.event LIKE 'load %')
) = 'load start') AS load_movement;
this is the query to get the time between start and end:
select sum(a.timestamp-b.timestamp) from Table1 a join Table1 b on a.rowid-b.rowid=1 and a.rowid%2=0 and a.event='movement end';
similary, between end and start:
select sum(a.timestamp-b.timestamp) from Table1 a join Table1 b on a.rowid-b.rowid=1 and a.rowid%2=1 and a.event='movement start';
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