日期列的 SQL 计数

Question

我有一个表，其中包含一组列，其中一个是日期列。

我需要计算该列的值引用同一个月的次数。如果一个月的计数总和超过 3，则返回。

例如：

____________________
| DATE   |  ....    |
---------------------
1998-09-02
1998-09-03
1998-10-03
1998-10-04

这必须不返回任何值。因为它没有必要的重复次数。

但它确实是这样的：

____________________
| DATE   |  ....    |
---------------------
1998-09-02
1998-09-03
1998-09-12
1998-09-14
1998-10-02
1998-11-21

11 月份。

适用于 Oracle DB。

Answer 1

SELECT
 COUNT(date)
 , TRUNC(DATE,'MON')
FROM TABLE
GROUP BY TRUNC(DATE,'MON')
HAVING COUNT(DATE) > 3

Answer 2

create table x (date_col date);

insert into x values (date '1998-09-02');
insert into x values (date '1998-09-03');
insert into x values (date '1998-09-12');
insert into x values (date '1998-09-14');
insert into x values (date '1998-10-02');
insert into x values (date '1998-11-21');

SELECT TRUNC(date_col,'MM'), count(*)
FROM x
GROUP BY TRUNC(date_col,'MM')
HAVING count(*) > 3;

Answer 3

那么，如果 3 哥伦布包含 1999-01-xx 您想获取它吗？

SELECT YEAR(date), MONTH(date) 
FROM table GROUP BY YEAR(date), MONTH(date) 
HAVING COUNT(*) > 3

如果您需要包含上方结果的所有行，它应该看起来像这样

SELECT * FROM table 
INNER JOIN (
   SELECT YEAR(date) as y, MONTH(date) as m 
   FROM table GROUP BY YEAR(date), MONTH(date) 
   HAVING COUNT(*) > 3
) as virtualTable 
ON virtualTable.y = YEAR(date) AND virtualTable.m = MONTH(date)

Answer 4

此示例将有所帮助：

create table d1
( event_date date, event_description varchar2(100));

insert into d1 values (sysdate,'Phone Call');
insert into d1 values (sysdate,'Letter');
insert into d1 values (sysdate-50,'Interview');
insert into d1 values (sysdate-50,'Dinner with parents');
insert into d1 values (sysdate-100,'Birthday');
insert into d1 values (sysdate-100,'Holiday');
insert into d1 values (sysdate-100,'Interview');
insert into d1 values (sysdate-100,'Phone Call');

commit;

select * from d1;

EVENT_DATE                EVENT_DESCRIPTION                                                                                    
------------------------- ----------------------------------------------- 
04-MAR-10 14.47.58        Phone Call                                                                                           
04-MAR-10 14.47.58        Letter                                                                                               
13-JAN-10 14.47.58        Interview                                                                                            
13-JAN-10 14.47.58        Dinner with parents                                                                                  
24-NOV-09 14.47.58        Birthday                                                                                             
24-NOV-09 14.47.58        Holiday                                                                                              
24-NOV-09 14.47.58        Interview                                                                                            
24-NOV-09 14.47.58        Phone Call                                                                                           
8 rows selected

您可以看到 Nov-09 是唯一有超过 3 个事件的月份。

回到您最初的问题，即如果一个月内的计数总和超过 3，则返回。以下 SQL 聚合将起作用。

select trunc(event_date,'MONTH'),count('x') from d1 
having count('x') > 3 group by trunc(event_date,'MONTH') 

或者，使用 to_char 将 Date 类型转换为带有 MON-YYYY 图片的 Char，如下所示：

select to_char(trunc(event_date,'MONTH'),'MON-YYYY') month,
    count('x') no_of_occurances from d1 having count('x') > 3 group trunc(event_date,'MONTH') 

Answer 5

理想情况下，您应该创建一个接受您需要的两个条件的存储过程，月份（整数）和限制（整数）

在执行以下命令的参数化过程中

 SELECT MONTH(Date) AS TheMonth, COUNT(MONTH(Date)) AS TheMonthCount
    FROM MyTable
    GROUP BY MONTH(Date)
    HAVING (COUNT(MONTH(Date)) > @limit) AND (MONTH(Date) = @month)

要还输出相关月份，您可以使用以下命令

SELECT CAST(YEAR(Date) AS NVARCHAR) + '.' + 
       CAST(MONTH(Date) AS NVARCHAR) AS 'The  ', 
MONTH(Date ) AS TheMonth, COUNT(MONTH(Date)) AS TheMonthCount
    FROM Audit_Entry
    GROUP BY MONTH(Date), 
         CAST(YEAR(Date) AS NVARCHAR) + '.' +            
         CAST(MONTH(Date) AS NVARCHAR)
    HAVING (COUNT(MONTH(Date)) > @limit) AND (MONTH(Date) = @month)

Answer 6

这应该适用于 mysql 和 mssql：

SELECT MONTH(date), Sum(MONTH(date))
FROM table
GROUP BY date
HAVING Sum(MONTH(date)) > 3

Answer 7

我不确定您使用的是哪个数据库。

在 MySQL 中，查询将类似于 @THEn 提出的方法。

在 SQL Server 上，您还有其他有趣的可能性。

阅读这篇文章了解更多详情。

Answer 8

您可以使用 Oracle 的 EXTRACT 方法：

select theMonth, sum(monthCount)
from (
  select 
    extract(MONTH FROM t.theDateColumn) as theMonth,
    1 as monthCount
  )
group by theMonth
having sum(monthCount) >= 3

我手头目前没有 Oracle 数据库，因此此代码可能无法按原样工作 - 对此我深表歉意。

Answer 9

可能是错误的，但猜测：

SELECT SUM(date) FROM table
GROUP BY date where SUM(date) > 3