使用来自选择的值的Mysql更新[重复]

Question

我有一个天气应用程序，我每小时将气象数据存储在数据库中。

最近我发现了一个小错误，导致写入了数百条错误记录。

为了解决这个问题，我决定使用当天的平均值更新所有错误记录。

我有以下 3 个查询来检索我需要的值：

select TRUNCATE( ( sum(temperature) / count(*) ), 2) as myTempAvg  from MY_TABLE where rawData not in ('chron', 'fallback') and DATE(transmissionDate) = DATE('2019-01-27');
select TRUNCATE( ( sum(humidity) / count(*) ), 2) as myHumyAvg  from MY_TABLE where rawData not in ('chron', 'fallback') and DATE(transmissionDate) = DATE('2019-01-27');
select TRUNCATE( ( sum(pressure) / count(*) ), 0) as myPressAvg  from MY_TABLE where rawData not in ('chron', 'fallback') and DATE(transmissionDate) = DATE('2019-01-27');

我正在尝试找出一种在 UPDATE 语句中使用上述查询的方法。比如：

update MY_TABLE set temperature = $QUERY_1_RESULT , humidity = $QUERY_2_RESULT , pressure = $QUERY_3_RESULT where rawData in ('chron', 'fallback')  and DATE(transmissionDate) = DATE('2019-01-27');

注意：$QUERY 变量用于解释用途占位符。

有什么想法吗？

Answer 1

您应该能够按照以下方式进行操作。

INSERT INTO MY_TABLE (temperature)
SELECT TRUNCATE( ( sum(temperature) / count(*) ), 2) as myTempAvg  
FROM MY_TABLE 
WHERE rawData not in ('chron', 'fallback')
AND DATE(transmissionDate) = DATE('2019-01-27');

Answer 2

你可以试试下面-

update MY_TABLE 
(
select TRUNCATE( ( sum(temperature) / count(*) ), 2) as myTempAvg ,
TRUNCATE( ( sum(humidity) / count(*) ), 2) as myHumyAvg,
TRUNCATE( ( sum(pressure) / count(*) ), 0) as myPressAvg
from MY_TABLE 
where rawData not in ('chron', 'fallback') and DATE(transmissionDate) = DATE('2019-01-27')
)as src
set temperature=myTempAvg ,humidity = myHumyAvg , pressure = myPressAvg
where rawData in ('chron', 'fallback')  and DATE(transmissionDate) = DATE('2019-01-27')