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 Computed Column Always has 0.00 Value

Author  Topic 

mcujardo
Starting Member

5 Posts

Posted - 2012-01-09 : 03:04:50
Hi,

I have this query below, basically my main concern is this line on the query that I have posted:

CAST((SUM(duration) / DATEDIFF(minute, '2011-12-01', '2011-12-08')) AS DECIMAL(2, 2)) AS 'DowntimePercentage'

My goal is to calculate the Downtime Percentage using the statement but, when I execute the query below, the column always has 0.00 value.

Can you help me or guide me on what I've done wrong and how to correct it?

Thanks


SELECT SUM(duration) AS DowntimeDuration
, COUNT(util_reas.reas_desc) AS Frequency
, CAST((SUM(duration) / DATEDIFF(minute, '2011-12-01', '2011-12-08')) AS DECIMAL(2, 2)) AS 'DowntimePercentage'
, util_reas.reas_desc AS DownDescription
FROM
(SELECT cust_util_log.event_time_local
, cust_util_log.state_cd
, cust_util_log.reas_cd
, cust_util_log.duration
, cust_util_log.raw_reas_cd
, cust_util_log.ent_id FROM cust_util_log
UNION
SELECT util_log.event_time_local
, util_log.state_cd
, util_log.reas_cd
, util_log.duration
, util_log.raw_reas_cd
, util_log.ent_id FROM util_log) cust_util
JOIN [site] ON cust_util.ent_id = [site].ent_id
JOIN util_reas ON util_reas.reas_cd = cust_util.reas_cd
WHERE cust_util.state_cd = 5
AND (event_time_local BETWEEN '2011-12-01' AND '2011-12-08')
AND [site].site_name ='Lanco 3'
GROUP BY util_reas.reas_desc
ORDER BY [Frequency] DESC

visakh16
Very Important crosS Applying yaK Herder

52326 Posts

Posted - 2012-01-09 : 03:58:53
try like below


..
CAST((SUM(duration)* 1.0 / DATEDIFF(minute, '2011-12-01', '2011-12-08')) AS DECIMAL(2, 2)) AS 'DowntimePercentage'
...


------------------------------------------------------------------------------------------------------
SQL Server MVP
http://visakhm.blogspot.com/

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madhivanan
Premature Yak Congratulator

22864 Posts

Posted - 2012-01-09 : 08:12:06
This is the reason
http://beyondrelational.com/blogs/madhivanan/archive/2008/01/16/beware-of-implicit-conversions.aspx

Madhivanan

Failing to plan is Planning to fail
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