在MySQL中按月份和年份分組

Question

給定一個每行有時間戳的表，如何格式化查詢以適應特定的json對象格式。

我想組織一個json對象成幾年/幾個月。

JSON立足查詢關：

{ 
    "2009":["August","July","September"], 
    "2010":["January", "February", "October"] 
} 

下面是該查詢我到目前爲止 -

SELECT 
    MONTHNAME(t.summaryDateTime) as month, YEAR(t.summaryDateTime) as year 
FROM 
    trading_summary t 
GROUP BY MONTH(t.summaryDateTime) DESC"; 

查詢被打破，因爲它（不出所料）不同年份混爲一談。使用

GROUP BY year, month DESC"; 

而不是

GROUP BY MONTH(t.summaryDateTime) DESC"; 

Answer 1

GROUP BY YEAR(t.summaryDateTime), MONTH(t.summaryDateTime) DESC; 

Answer 2

是你想要的。

Answer 3

您每月只進行分組，您必須通過

Answer 4

SELECT YEAR(t.summaryDateTime) as yr, GROUP_CONCAT(MONTHNAME(t.summaryDateTime)) AS month 
FROM trading_summary t GROUP BY yr 

添加YEAR（）到該組還有你需要處理它在外部腳本獲得正是你要尋找的結構。

例如使用PHP的爆炸來創建月份名稱的列表數組，然後使用json_encode（）

Answer 5

你必須做這樣的事情

SELECT onDay, id, 
sum(pxLow)/count(*),sum(pxLow),count(`*`), 
CONCAT(YEAR(onDay),"-",MONTH(onDay)) as sdate 
FROM ... where stockParent_id =16120 group by sdate order by onDay 

Answer 6

SELECT MONTHNAME(t.summaryDateTime) as month, YEAR(t.summaryDateTime) as year 
FROM trading_summary t 
GROUP BY YEAR(t.summaryDateTime) DESC, MONTH(t.summaryDateTime) DESC 

應該使用DESC爲獲得正確的訂單。

Answer 7

使用EXTRACT函數這樣

mysql> SELECT EXTRACT(YEAR FROM '2009-07-02'); 
     -> 2009 

Answer 8

我喜歡

SELECT 
    MONTHNAME(t.summaryDateTime) as month, YEAR(t.summaryDateTime) as year 
FROM 
    trading_summary t 
GROUP BY EXTRACT(YEAR_MONTH FROM t.summaryDateTime) DESC"; 

Answer 9

GROUP BY DATE_FORMAT(summaryDateTime,'%Y-%m')