September 20, 2008 at 11:35 am
Hi All
What is the logic behind, When you compare string using logical operation >= , below are the some different examples.
Actually, i was thinking i will convert into Ascii value and compare but it not true.
If you have any information or document or link regarding this, please keep forward.
Queries
drop
table tt
create
table tt
(
fname varchar(70),
onechar
char(1)
)
insert
into tt values('azint','a')
insert
into tt values('hemang','h')
insert
into tt values('kumar','k')
insert
into tt values('manoj','m')
insert
into tt values('yanoj','y')
select
ascii(fname),ascii(onechar),* from tt
select
ascii(fname),ascii(onechar),ascii('m'),* from tt where fname >= 'm'
select
ascii(fname),ascii(onechar),ascii('mz'),* from tt where fname >= 'mz' --Query 1
select
ascii(fname),ascii(onechar),ascii('mz'),* from tt where ascii(fname) >= ascii('mz') --Query--2
If It converts in ascii and compare than query(Query 1,Query--2) would have same result....but it is not.
Any help will be appreciated
Thank
Manoj kumar
September 20, 2008 at 2:45 pm
The ASCII() function only returns the ASCII integer value of the first character:
select ascii('m'), ascii('mz')
----------- -----------
109 109
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September 21, 2008 at 9:00 am
And besides all that, the answer of what happens when you compare strings with >= entirely depends on your collation setting.
under normal circumstances >= in varchar/nvarchar means further down the list in a descending sort
like so:
if 'aaaa' > = 'abbb'
print 'aaaa is greater than or equal to bbbb'
else
print 'it isnt'
Craig Outcalt
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