Improve company productivity with a Business Account.Sign Up

x
  • Status: Solved
  • Priority: Medium
  • Security: Public
  • Views: 364
  • Last Modified:

converting varchar to int to extract records

Hi everyone

I have attached a piece of code which I use to calculate students start_time, end_time, time late, time absent and so on for each day.  My aim is to find students who have been absent for longer than 4 hours per day (which is why I write all the records into the temp table #students then select from here which students have been absent 4 hours).  My problem is because absent is a varchar it wont let me compare to see if absent > 4 as I get the following error

Msg 8114, Level 16, State 5, Line 80
Error converting data type varchar to numeric.

Can anyone help me fix this?

Thanks
if object_id('tempdb..#students','U') is not null drop table #students

SELECT student_id, date, week_no, [start time], [end time], CONVERT(VARCHAR(5), [Late], 108) AS 'Late',
	CONVERT(VARCHAR(5), [Absent], 108) AS 'Absent'

into #students

FROM
(
	SELECT  student_id, Date,week_no, 
		MIN(CONVERT(datetime, start_time)) AS 'Start Time', 
		MAX(CONVERT(datetime, End_Time)) AS 'End Time',
		DateAdd(n, SUM(CASE WHEN attendance_type = 'LA' THEN late_minutes ELSE 0 END), 0) AS 'Late',
		DateAdd(n, SUM(CASE WHEN attendance_type IN ('AA', 'AB') THEN DATEDIFF(minute, start_time,  end_time) ELSE 0 END) 
			+ SUM(CASE WHEN attendance_type = 'LA' THEN late_minutes ELSE 0 END), 0) AS 'Absent'
		FROM allstudents

	GROUP BY student_id, Date, week_no
) X	 


select *

from #students

where Absent > 4

Open in new window

0
lisa_mc
Asked:
lisa_mc
3 Solutions
 
CrowerCommented:

The following link may help. It explains in 2 functions to convert formats and some examples.

I hope it helps


http://msdn.microsoft.com/en-us/library/ms187928.aspx
0
 
RimvisCommented:
Or try this:

where Absent > '04:00'
0
 
appariCommented:
try this,
if object_id('tempdb..#students','U') is not null drop table #students

SELECT student_id, date, week_no, [start time], [end time], CONVERT(VARCHAR(5), [Late], 108) AS 'Late',
	CONVERT(VARCHAR(5), [Absent], 108) AS 'Absent'

into #students

FROM
(
	SELECT  student_id, Date,week_no, 
		MIN(CONVERT(datetime, start_time)) AS 'Start Time', 
		MAX(CONVERT(datetime, End_Time)) AS 'End Time',
		DateAdd(n, SUM(CASE WHEN attendance_type = 'LA' THEN late_minutes ELSE 0 END), 0) AS 'Late',
		DateAdd(n, SUM(CASE WHEN attendance_type IN ('AA', 'AB') THEN DATEDIFF(minute, start_time,  end_time) ELSE 0 END) 
			+ SUM(CASE WHEN attendance_type = 'LA' THEN late_minutes ELSE 0 END), 0) AS 'Absent'
		FROM allstudents

	GROUP BY student_id, Date, week_no
) X	 


select *

from #students

where datepart(hh,convert(datetime,Absent)) > 4

Open in new window

0
 
lisa_mcAuthor Commented:
Hi rimvis - worked perfect thanks so I picked this as my main answer

Hi appari - I also accepted this as it shows another way of doing things
but one correction instead of
where datepart(hh,convert(datetime,Absent)) > 4
I needed
where datepart(hh,convert(datetime,Absent)) >= 4
because the line >4 only selects times 5 hours or more but I needed 4 hours or more therefore I needed >=4

Hi Crower - thanks for the reference

Thanks very much guys for the prompt answers really appreciate it
0
Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.

Join & Write a Comment

Featured Post

Improve Your Query Performance Tuning

In this FREE six-day email course, you'll learn from Janis Griffin, Database Performance Evangelist. She'll teach 12 steps that you can use to optimize your queries as much as possible and see measurable results in your work. Get started today!

Tackle projects and never again get stuck behind a technical roadblock.
Join Now