General information
Category:
Databases,Tables, Views, Indexing and SQL syntax
Title:
How to check previous record value
Hi All;
I have a several hundreds thousands records in a table which I need to compare the closing value of each record with the previous one.
I used the following code
Option 1
go top
scan
nVal1 = nClsVal
skip
nVal2 = nClsVal
skip -1
rest of code
endscan
too slow.
option2
select A.*, 000000000 as nRecNo from table1 to Cursor cTbl_1 readwrite
then replace the nRecNO with Recno() all
select A.*, 000000000 as nRecNo from table1 to Cursor cTbl_2 readwrite
then replace the nRecNO with Recno()-1 all
Finally
select a.*, b.nClsVal as nPrvVal ;
from cTbl_1 a, cTbl_2 b ;
where a.nRecNo = b.nRecNo ;
into cursor cTmp
This is far more faster than option 1 but done in 3 sql select statement.
Is there is any suggestion for a more elegent way
Thanks all
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