在MySQL中按月份和年份分组

Question

给定一个每行有时间戳的表，如何格式化查询以适应特定的json对象格式。

我想组织一个json对象成几年/几个月。

JSON立足查询关：

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

下面是该查询我到目前为止 -

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

查询被打破，因为它（不出所料）不同年份混为一谈。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

您每月只进行分组，您必须通过

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（）到该组还有你需要处理它在外部脚本获得正是你要寻找的结构。

例如使用PHP的爆炸来创建月份名称的列表数组，然后使用json_encode（）

Answer 5

你必须做这样的事情

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 

应该使用DESC为获得正确的订单。

Answer 7

使用EXTRACT函数这样

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

Answer 8

我喜欢

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')