mysql將兩個查詢合併爲一個查詢

Question

我有兩個工作查詢。第一個選擇特定月份的觀測溫度。第二個選擇當月每一天的正常平均值。

SELECT data, Tmax, Tmin, Mitjana, Pluja 
FROM $estacio 
WHERE data BETWEEN '2014-03-01' AND '2014-03-31' 

---

SELECT data, round(avg(Mitjana),1) 
FROM $estacio 
WHERE month(data)='03' 
group by day(data), month(data) 
order by data 

我試圖找到進入第一查詢作爲新列觀察到平均與正常AVG和插入之間的區別。 （Mitjana的意思是）

Answer 1

只需將第二個查詢添加到第一個查詢。

SELECT data, Tmax, Tmin, Mitjana, Pluja, (
    (SELECT NormalAvg FROM 
    (SELECT data, round(avg(Mitjana),1) AS NormalAvg FROM $estacio 
    WHERE month(data)='03' 
    group by day(data), month(data) order by data) AS NormalAvgList 
    WHERE NormalAvgList.data=est.data LIMIT 1)-Mitjana) AS Diff 
    FROM $estacio AS est WHERE data BETWEEN '2014-03-01' AND '2014-03-31' 

測試SQL Fiddle。