Please explain followin in convert datetime case.

Question

hi,
Q1)followng is from https://msdn.microsoft.com/en-IN/library/ms187928.aspx?f=255&MSPPError=-2147217396
please explain "1 These
style values return nondeterministic results. Includes all (yy) (without century) styles and a subset of (yyyy) (with century) styles."
Q2) please explain with ex
Styles greater than 100 are deterministic, except for styles 106, 107, 109 and 113.
yours sincerley

Answer 1

Non deterministic means the result of the function can depend on something other than the input to the function.  So for styles of 100 or greater the result is non deterministic if that style returns the month as text (because different language settings
return different abbreviations for the month name.  Kalman gave you an example of that.
The styles with 2 digit years are non deterministic because the result returned depends on the value of the "two digit year cutoff" option.  See
https://msdn.microsoft.com/en-us/library/ms191004.aspx for a discussion of that option.  SQL uses that option when you convert a two digit year into a date.  So changing that option
can cause the result to change.  For example suppose you convert '350517' using style 1.  With the default two digit year cutoff of 2049, CONVERT() of '350517' using style 1 will return 2035-05-17, but if you change the two digit year cutoff to 2030,
CONVERT() of '350517' using style 1 will return 1935-05-17.
If you want to play with changing the cutoff date the above link tells you how to change it.  But if you do, be very careful and do NOT change it on a production server.  Changing that option will affect every connection to every database on that
server instance.  You can easily break running code.
Tom