Question

您好我有以下MySQL查询：

SELECT sensorNumber, rangeStartTime, rangeEndTime, sensorLow, sensorAverage, sensorHigh 
FROM rangeData 
WHERE rangeStartTime >= 0 
AND rangeEndTime <= 43200 
AND (sensorNumber = 3)
ORDER BY sensorNumber;

我怎样才能在rangeStartTime和rangeEndTime时间范围之外只抓取1个上一个和下一个值？

所以在英语中这可以说是：“在下午5:00和晚上7:00之间选择所有值，也在下午5:00之前选择下一个值，在晚上7:00之后选择下一个值。 “

我通过查看其他示例尝试以下操作，但它不起作用：

SELECT sensorNumber, rangeStartTime, rangeEndTime, sensorLow, sensorAverage, sensorHigh 
FROM rangeData 
WHERE rangeStartTime >= 0 
AND rangeEndTime <= 43200 
AND rangeStartTime < 0 LIMIT 1
AND rangeEndTime > 43200 LIMIT 1
AND (sensorNumber = 3)
ORDER BY sensorNumber;

每个查询都会增加5-10秒的等待时间，所以我想把它变成一个查询。

Answer 1

你可以通过3个查询的简单联合来做到这一点，原始的一个，一个用于前一个，一个用于下一个：

(SELECT sensorNumber, rangeStartTime, rangeEndTime, sensorLow, sensorAverage, sensorHigh 
FROM rangeData 
WHERE (rangeStartTime BETWEEN 0 AND 43200) AND (sensorNumber = 3))
UNION
(SELECT sensorNumber, rangeStartTime, rangeEndTime, sensorLow, sensorAverage, sensorHigh 
FROM rangeData 
WHERE (rangeStartTime < 0) AND (sensorNumber = 3)
ORDER BY rangeStartTime DESC
LIMIT 1)
UNION
(SELECT sensorNumber, rangeStartTime, rangeEndTime, sensorLow, sensorAverage, sensorHigh 
FROM rangeData 
WHERE (rangeStartTime > 43200) AND (sensorNumber = 3)
ORDER BY rangeStartTime ASC
LIMIT 1)
ORDER BY sensorNumber;

（顺便说一句：由于您只查询了一个ORDER BY，因此不需要sensorNumber

在一个Query中，MySQL SELECT值在范围AND下一个值范围之外

1 个答案: