Big ugly cursor - sql

Question

I'm populating a table of about 15 columns from a table of about 1000 columns. I need to grab the time from the big table. That time is broken up into minutes and hours [rn-min] and [rn-hr] and I need them in an am/pm format in the new table. The table is populated by an outside company so I can't really change much about it, I did get them to put in a transferred column for me to check. It's big and slow and I only need a few columns and there is a lot of duplicate/similar rows. In any case I'm making the smaller table from the bigger table. I wrote a cursor, its slow and I was wondering if there was a better way to do it. I can't just use a simple insert(select columns) because I want to change the way the time and date are stored. Thanks, any help or advice is appreciated
declare data CURSOR READ_ONLY FORWARD_ONLY
for
select [raID],
(otherfields),
CAST([RA-rent-mm] as varchar(2)) + '/' + CAST([RA-rent-dd] as varchar(2)) + '/' +
CAST([RA-Rent-CC] as varchar(2)) + CAST([RA-RENT-YY] as varchar(2)) [Date_Out],
CAST([RA-Rtrn-mm] as varchar(2)) + '/' + CAST([RA-Rtrn-dd] as varchar(2)) +
'/' + CAST([RA-Rtrn-CC] as varchar(2)) + CAST([RA-Rtrn-YY] as varchar(2)) [Date_In],
CAST([RA-RENTAL-HOURS] as varchar(2)),
CAST([RA-RENTAL-Minutes] as varchar(2)),
CAST([RA-RTRN-HOURS] as varchar(2)),
CAST([RA-RTRN-MINUTES] as varchar(2)),
(other fields)
from table_name
where Transfered is null
and [RA-rtrn-mm] != 0 --this keeps me from getting the duplicate/similar rows, once this doesn't equal 0 there aren't anymore rows so I just grab this one
declare #sql as varchar(max)
declare #raID int;
(other fields),
declare #rentDate varchar(8);
declare #rtrnDate varchar(8);
declare #rentHours varchar(2);
declare #rentMinutes varchar(2);
declare #rtrnHours varchar(2);
declare #rtrnMinutes varchar(2);
(other fields)
open data
fetch next from data into
#raID,
(other fields),
#rentDate ,
#rtrnDate ,
#rentHours ,
#rentMinutes ,
#rtrnHours ,
#rtrnMinutes ,
(other fields),
while ##FETCH_STATUS = 0
begin
set #rentMinutes = left('0' + #rentMinutes,2);--padding with 0 if minutes is 1-9
set #rtrnMinutes = left('0' + #rtrnMinutes,2);
--turning the varchar times into a time then back to varchar with correct am/pm notation
declare #rentT time = #rentHours + ':' + #rentMinutes;
declare #rtnT time = #rtrnHours + ':' + #rtrnMinutes;
declare #rentTime varchar(7) = convert(varchar(15),#rentT, 100);
declare #returnTime varchar(7) = convert(varchar(15),#rtnT, 100);
--print #rentTime;
set #sql = 'INSERT other_tbl_name(raID, (other fields), Date_Out, Date_In, Time_Out, Time_In, (other fields))
values ('+cast(#raID as varchar(max))+', (other fields),'''+#rentDate+''',
'''+#rtrnDate+''', '''+#rentTime+''', '''+#returnTime+''',
(other fields))';
--exec(#sql)
print #sql
--need a way to make sure the insert worked before updating
--need to update transferred to keep from updating the same info
declare #update as varchar(max) = '
UPDATE Capture.icokc_data
SET Transfered = 1
WHERE [raID] = '+cast(#raID as varchar(10))
--exec(#update)
--print #update
fetch next from data into
#raID,
(other fields)
#rentDate ,
#rtrnDate ,
#rentHours ,
#rentMinutes ,
#rtrnHours ,
#rtrnMinutes ,
(other fields)
end
close data;
deallocate data;

Answer 1

Why dont you bulk insert it, and transform the dates and times in the select?
Something like this:
INSERT other_tbl_name(raID, (other fields), Date_Out, Date_In, Time_Out, Time_In, (other fields))
select
[raID],
(otherfields),
CAST([RA-rent-mm] as varchar(2)) + '/' + CAST([RA-rent-dd] as varchar(2)) + '/' + CAST([RA-Rent-CC] as varchar(2)) + CAST([RA-RENT-YY] as varchar(2)) [Date_Out],
CAST([RA-Rtrn-mm] as varchar(2)) + '/' + CAST([RA-Rtrn-dd] as varchar(2)) + '/' + CAST([RA-Rtrn-CC] as varchar(2)) + CAST([RA-Rtrn-YY] as varchar(2)) [Date_In],
CONVERT(varchar(15),DATEADD(minute, [RA-RENTAL-Minutes], DATEADD(hour, [RA-RENTAL-HOURS], '00:00')), 100) as [Time_out],
CONVERT(varchar(15),DATEADD(minute, [RA-RTRN-MINUTES], DATEADD(hour, [RA-RTRN-HOURS], '00:00')), 100) as [Time_in],
(other fields)
from table_name
where Transfered is null
and [RA-rtrn-mm] != 0
UPDATE Capture.icokc_data
SET Transfered = 1
WHERE [raID] IN
(
select
[raID]
from table_name
where Transfered is null
-- and [RA-rtrn-mm] != 0 -- not sure about this one
)

Answer 2

As it's a direct conversion, i.e. one record in and one record out, I don't really see any reason why it couldn't be done with a single insert query.
Anyhow, don't create queries dynamically. The dynamic queries will be parsed and planned for each iteration, which is most likely the reason for most of the performance problems.
For example, instead of:
declare #update as varchar(max) = '
UPDATE Capture.icokc_data
SET Transfered = 1
WHERE [raID] = '+cast(#raID as varchar(10))
exec(#update)
just do:
UPDATE Capture.icokc_data
SET Transfered = 1
WHERE [raID] = #raID