I want convert this table (Reading):
x
ID TimeTable_ID reading_Value Sensor_ID
1 1 482 1
2 1 153 2
3 1 152 3
4 1 781 4
5 2 156 1
6 2 842 2
7 2 157 3
8 2 453 4
into this:
TimeTable_ID Sensor_1 Sensor_2 Sensor_3 Sensor_4
1 482 153 152 781
2 156 842 157 453
My try:
SELECT *
FROM (SELECT TimeTable_ID, reading_Value
FROM Reading
) AS BaseData PIVOT
(COUNT(reading_Value) FOR TimeTable_ID IN ([Sensor_1], [Sensor_2], [Sensor_3], [Sensor_4])
) AS PivotTable;
but it does not work.
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Answer
MySQL does not support the PIVOT
operator. But, you may use a standard pivot query instead:
SELECT
TimeTable_ID,
MAX(CASE WHEN Sensor_ID = 1 THEN reading_Value END) AS Sensor_1,
MAX(CASE WHEN Sensor_ID = 2 THEN reading_Value END) AS Sensor_2,
MAX(CASE WHEN Sensor_ID = 3 THEN reading_Value END) AS Sensor_3,
MAX(CASE WHEN Sensor_ID = 4 THEN reading_Value END) AS Sensor_4
FROM Reading
GROUP BY TimeTable_ID;