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Increasing by percentage


im trying to update one of the records in my table 'City' called 'Population' by 5%.

Population= Population * 1.05;

The calculation seems correct but its just the final result which seems to not have proper rounding.

for example
one of the records in 'Population' is 1.659.000
after i use the update function my final answer comes out to 1.74195 rather than 1.741.950
Mar 16 '11 #1
1 2404
code green
1,726 Expert 1GB
This is because of the way computers handle floating point numbers.
This is a full lecture on any computer science module and is worth a little research if interested.

Suffice to say do not trust the return values from any calculation or comparison involving floating point numbers.

ROUND seems an obvious solution but this does not work on my system.
I use CAST(.............. AS DECIMAL(10,4))
which returns numbers to 4 decimal places.
Mar 16 '11 #2

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