Question

My dates are varchar(50) and appear like this in my database:

2/15/2012

The table looks like this: (Note: someid is not a primary key, its identifies a group)

 |  someid  |   date     |  float_value  | 
 |   1      | 2/15/2012  |     3.2       |   
 |   1      | 2/15/2012  |     1.4       |
 |   1      | 2/15/2012  |     2.1       |
 |   1      | 2/16/2012  |     1.8       |

How would I do something like this:

select avg(date), avg(float_value)
where someid = 1

To return something like this:

|  date     |  float_value  |
| 2/15/2012 |   2.126       |     

Perhaps the answer isn’t average date, but like the date the occurs the most often (in terms of the someid).

Any help would be appreciated from the sql experts.

Thanks in advance

Answer 1

Forget the float nonsense. How about:

SELECT DATEADD(DAY, AVG(DATEDIFF(DAY, 0, create_date)), 0) FROM sys.objects;

In your case you’ll need to convert first. E.g.

SELECT 
  avg_date = DATEADD(DAY, AVG(DATEDIFF(DAY, 0, CONVERT(SMALLDATETIME, [date]))), 0) 
FROM dbo.yourtable
WHERE someid = 1;

This variation may also be useful:

SELECT 
  someid, 
  avg_date = DATEADD(DAY, AVG(DATEDIFF(DAY, 0, CONVERT(SMALLDATETIME, [date]))), 0) 
FROM dbo.yourtable
GROUP BY someid;

EDIT to present the exact precise and particular formatting that seems to be necessary:

SELECT 
  avg_date = CONVERT(CHAR(10), 
    DATEADD(DAY, AVG(DATEDIFF(DAY, 0, CONVERT(SMALLDATETIME, [date]))), 0),
    101) 
FROM dbo.yourtable
WHERE someid = 1;