How to inner join two select queries on same table - sql

Question

I am stuck... A 'data' table with columns 'value' and 'datatype' is populated with engine load and vehicle speed and each record is stamped with date, time, lat, long. I want to query for engine load over 10% while the vehicle is moving (e.g. speed > 0). I can create a query to select the engine load and I can create a query to select the vehicle speed but how do I create a query to select engine load when > 10% AND the Vehicle is moving where their date, time lat, and long are equal?
This Query does not work, but it provides a jist of what I am trying to do. Can anyone help me create a query?
tables
TName: data
PK datakey
value
fk1 dataeventkey
fk2 datatypenamekey
TName: datatypename
PK datatypenamekey
datatypename
TName: dataevent
PK dataeventkey
datetime
lat
long
SELECT
d1.datetime
FROM
(data INNER JOIN datatypename ON data.datatypenamekey = datatypename.datatypenamekey
INNER JOIN dataevent ON dataevent.dataeventkey = data.dataeventkey) d1
WHERE
( d1.datatypename = "Engine Load [%]" AND d1.value > 10 )
INNER JOIN
SELECT
d2.datetime
FROM
(data INNER JOIN datatypename ON data.datatypenamekey = datatypename.datatypenamekey
INNER JOIN dataevent ON dataevent.dataeventkey = data.dataeventkey) d2
WHERE
( d2.datatypename = "Vehicle Speed [mph]" AND d2.value > 0 )
ON d1.datetime = d2.datetime

Answer 1

I'm not 100% sure I understand, but I think you just need to reference two instances of the same table. Kind of making some assumptions based on your SQL, but giving it a shot here:
SELECT
engineLoad.dateTime
FROM
(
SELECT
d.datakey,
de.datetime
FROM
data d
INNER JOIN datatypename dt ON data.datatypenamekey = dt.datatypenamekey
INNER JOIN dataevent de ON de.dataeventkey = d.dataeventkey
WHERE
d.value > 10 AND
dt.datatypename = "Engine Load [%]"
) engineLoad
INNER JOIN
(
SELECT
d.datakey,
de.datetime
FROM
data d
INNER JOIN datatypename dt ON data.datatypenamekey = dt.datatypenamekey
INNER JOIN dataevent de ON de.dataeventkey = d.dataeventkey
WHERE
d.value > 0 AND
dt.datatypename = "Vehicle Speed [mph]"
) vehicleSpeed
ON engineLoad.dataKey = vehicleSpeed.dataKey <==might need to remove this line
AND engineLoad.datetime = vehicleSpeed.datetime
Edit
Looks like you need to reference datatypename twice as well? Edited the above, so try again.