您可以使用窗口函数来查找每个sensorname/datetimeid组合的波长数量:
WITH Data AS
( SELECT W.DateTimeID,
S.SensorName,
S.SensorType,
W.Channel,
W.PeakNr,
W.Wavelength,
[Wcount] = COUNT(*) OVER(PARTITION BY s.SensorName, d.DateTimeID)
from tblWavelengths as W
LEFT JOIN tblSensorWavelengths as SW
ON W.tblWavelengthID = SW.WavelengthID
LEFT JOIN tblSensors as S
ON SW.SensorID = S.SensorID
)
SELECT DateTimeID, SensorName, SensorType, Channel, PeakNr, WaveLength
FROM Data
WHERE Wcount = 2
ORDER BY DateTimeID;
补充
我意识到你可能会在同一时间使用相同波长的传感器获得两个结果,这将返回2条记录,但没有两个不同的波长。由于窗口函数不支持使用DISTINCT
,下面是另一种选择。
WITH Data AS
( SELECT W.DateTimeID,
S.SensorName,
S.SensorType,
W.Channel,
W.PeakNr,
W.Wavelength,
W.tblWaveLengthID
from tblWavelengths as W
LEFT JOIN tblSensorWavelengths as SW
ON W.tblWavelengthID = SW.WavelengthID
LEFT JOIN tblSensors as S
ON SW.SensorID = S.SensorID
)
SELECT d.DateTimeID, d.SensorName, d.SensorType, d.Channel, d.PeakNr, d.WaveLength
FROM Data d
INNER JOIN
( SELECT DateTimeID, SensorName
FROM Data
GROUP BY DateTimeID, SensorName
HAVING COUNT(DISTINCT tblWaveLengthID) = 2
) t
ON t.DateTimeID = d.DateTimeID
AND t.SensorName = d.SensorName
ORDER BY d.DateTimeID;