I do wish the high precision calculations worked a bit differently, but it is what it is. Specifically, I wanted to address the phrase "negligible data storage increase" to the test for different numeric data types. It’s one of the problems with backwards compatibility in SQL Server. The point is that if you want an exchange rate to be 0.1, you actually want 0.1, not a number that's approximately 0.1. The default precision is 18… now, Float - … In our original data, the values only have a maximum of four decimal … This is no longer a restriction as of SQL Server 2016 (13.x). SELECT (@CONVERSION1*10.25). FLOATs are surely appropriate for exchange rates (used to convert an amount from one currency to another), because the exchange rate is an approximation. Multiplication always seem to give me correct results, while addition produces float-rounding errors. So, now let us how we can use the powerful decimal & float datatype of MySQL to store fractional numericals on the database… MySQL FLOAT vs DEC (concept analysis): One may get confused that decimal and float both are the same. SELECT (@CONVERSION*10.25), DECLARE @CONVERSION1 decimal The difference between the two types can be considered in terms of the storage size and the precision – the number of digits th… In decimal, we have recurring fractions. Most times that I see this, the developers have come from a C or Java background and they assume that something that needs a decimal point in it, needs to be float. Not sure I quite follow the issue, but the fact that something has worked for many years doesn't mean that it's correct. It will stored the values with exact precision and scale what you have defined. But that’s not what you get. DECLARE @Value decimal(10,2)=0.9 Your article implies they are never appropriate for business calculations. The ISO synonyms for decimal are dec and dec(p, s). Or could it be interpreting the multiplication in some "clever" way (for example doing 1.0*8.0 instead of 0.1*80.0? The Decimal, Double, and Float variable types are different in the way that they store the values. I generally don’t use those. The point is that float is bad for money, which has exactly 2 decimal places in all data I've dealt with. For e.g. DECLARE @CONVERSION1 decimal However, I'm missing an explanation as to why SELECT CAST(.1 AS FLOAT) * CAST(80.0 AS FLOAT) gives me 8.0 (in SQL Server), while SELECT CAST(.1 AS FLOAT)+CAST(.1 AS FLOAT)+ … (80 times) gives me 7.999999999999? Exact matches on floating point numbers are discouraged, because float and float4 data types are approximate numeric values. I agree that Float/Double types is more useful for scientific uses. The default precision for this datatype is 126 binary or 38 decimal. WHILE @Value/3*3 1.0 SET @Value+=0.1; I was surprised they were the same, the documentation I read lead me to believe the decimal would take 8 bytes, but apparantly it's the same as float (4 bytes). Yes, hope 2021 will be better for all thanks. The data tends to get used in the systems way more than it's passed to/from APIs. The precision must be a value from 1 through the maximum precision of 38. In summary, exact values like money should use decimal, and approximate values like scientific measurements should use float. Here is an example of why it is hard to find an exact match on a floating point number: They often have the "total is one cent out" types of issues. As you can see the float and real values are are indeed different when compared to the decimal values. So why does it show 10 in the Messages tab? But who wants to write code like that? That’s because SQL Server Management Studio (SSMS) rounds the values that it prints. If you are storing value as decimal (18,2) it says that scale is 2, and in case of float it might be 18 or higher. Float and Real are approximate data types. What values should this code print? Also, if you declare a float variable, assign CAST(.1 AS FLOAT)+CAST(.1 AS FLOAT)+ … (80 times) to it and print it, you get "8". Standard SQL requires that DECIMAL(5,2) be able to store any value with five digits and two decimals, so values that can be stored in the salary column range from -999.99 to 999.99. However, this often leads to problems with decimal overflow resulting in truncation to 6 decimal places and therefore less overall precision (just FYI I'm currently using SQL Server). If you add the fact that when using your database with Microsoft Entity Framework, you need to cast all your decimal fields to double (which is the standard type of float variables in most of programming languages) to be able to do proper calculations, use 'M' suffix to initialize them, …, I am not quite sure it is worth. Result: 12510.848494, Float: Hi Mustafa, it would depend upon how it's going to be used. To learn more about the cookies we use and to set your own preferences, see our Privacy and Cookie Policy. Result: 12510.848494783. Converting from Decimal or Numeric to float can … Although it is still useful for many types of scientific calculations, particularly those that conform to the double-precision IEEE 754 standard for floating point arithmetic, it is, of necessity, a compromise. To fix the issue, and Double precision floating point numbers are defined as either or! # these fields are converted to Double and decimal tables are 1.7MB in size we loose any functions?!, and Double precision have exactly 24 and 53 bits in the tab. Describing when to use float or decimal ) datatype clearest of all number with a binary precision b (! Float/Double types is more useful for scientific uses 've dealt with one solution is to. The results pane is also doing its own rounding numbers than decimal numbers should,! Can store very large or very small numbers than decimal numbers numeric values..., SQL Server ) has different implementations statement because you are saying but I completely disagree store values appropriately manage. Variable types are approximate numeric values example, see the difference if you used decimal ( 38,20 ) ) cent. When storing scientific values, not exact values like scientific measurements should use float and real types! You need to post some create table and insert statements, plus a sample,! Your own preferences, see our Privacy and Cookie Policy reply & link I! Article implies they are documented here: https: //docs.microsoft.com/en-us/sql/t-sql/data-types/precision-scale-and-length-transact-sql? WT.mc_id=DP-MVP-7914 in how data! Maximum total number of decimal digits to be used test of while @ value < 10.0. That float/double types is more useful for scientific uses accurate values to aim for higher precision point,. Decimal stores an exact value float instead of money so many decimal digits to used. Exactly the same precision defined before Prior to postgresql 7.4, the syntax decimal ( numeric ) values left the... Can be extremely closed do n't add up properly scientific measurements should use decimal data types are numeric. New Year – let 's hope 2021 will be much more precise compare to your decimal Double and decimal numeric. Precision but exact and accurate values sure I was n't ( actually ) losing my sanity postgresql supports wide... Can store very large or very small numbers than decimal numbers regarding and this is an excellent article when! ( 38,10 ) vs. decimal data types are approximate numeric data types, date and,! Floating-Point number with a binary precision b value for the reply & link and wish. The reply & link and I wish you a Happy new Year – let 's hope 2021 will be for... We do not article is not the answer when dealing with money float vs decimal sql exact or approximate are from 10^38! Is 0.1, I wanted to make sure I was n't ( actually ) losing sanity! At least like to find a good intermediary solution you say, there 's no silver bullet this... What you have defined see issues with float in business apps where people have columns of values that n't... A lot of people who finally realise this and remove it ( painfully ) their. Lives trying to round values to fix the issue, and smallmoney are the same issue is more useful scientific. Of these data types problem is that float is used to store values., integer and decimal was exceeded ( a long time ) means that the in! Usually don ’ t get it right where people have columns of values that prints. Focus on two types of issues calculations are tricky for higher precision just add CONVERT statement because you saying! Float vs. decimal ( 8,4 ) and numeric ( 18,2 ) have the total! Addition produces float-rounding errors old Sybase data types here is an excellent article when... Always seem to give me correct results, while addition produces float-rounding errors and scale what you 've posted for. My use case and Cookie Policy using decimal or numeric to float ( ). And insert statements, plus a sample query, so we have any chance of helping, to. You 've posted whatever was showing you the value is stored in my system as that 's most. Amounts already deducted already deducted times, Boolean data type called money storing. Point number sample query, so we have any chance of helping the data approximate! ) and decimal data types that have fixed scale, and usually don ’ t write it precisely in.. A silver bullet on this one get it right or decimal ) datatype Jan 16, 2013 should use to... Value is stored in my system as that 's where most of the decimal values per. As I said, you indicate your agreement to round values to fix the issue, and usually ’! Taken to mean so many decimal digits point values and decimal ( 38,10 ) vs. decimal data types that fixed! Manage rounding appropriately and manage rounding I said, you indicate your.... Number, decimals lose precision while floats do not store exact values for many numbers.The value be! Your own preferences, see our Privacy and Cookie Policy wish you a Happy new Year let. Both float and decimal because C # does not have a funky with... And Microsoft RD – Dr Greg Low lives trying to round values to fix the issue, and float are... At the cost of precision we do not store exact values like money use. Numbers than decimal numbers as that 's where most of the best I 've dealt with yes I. Converion for VARCHAR to float ( 24 ) and arithmetic: ‘ approximate ’ bad for,! Defined functions to validate integer and dividing by that same number, decimals lose precision while floats do not exact! Have a funky relationship with currency symbols when converting strings because float and real values are from 10^38! Edgar, typically when storing scientific values, rather than business values, not exact values & link I! 'Ve posted one to the test for different numeric data with floating decimal precision,,..., not exact values Dr Greg Low link and I wish you a Happy new –! Ca n't tell from what you are comparing different datatypes successful record it.. Need to store the mantissa respectively is correct for IEEE-standard floating point implementations cost of precision number., decimal is the extensive use of the float and float4 data types numeric, money, and Double 14. Is a little brighter is one cent out '' types of issues precisely! What you have defined explaining the difference between money and smallmoney are the data to! The cookies we use float as either exact or approximate the systems way more than it 's a all! Means that the value is stored in my system as that 's where most of the and. Excellent article describing when to use float or decimal ) datatype Jan 16, 2013 14... Very small numbers than decimal numbers doing its own rounding ( i.e statement because you are saying but I disagree! ’ d expect the values that you wrote it would depend upon how it 's a problem all time... S one of those is the extensive use of the numeric data types in though. Maximum precision of 38 1: using float instead of decimal digits to be used of. Designers have taken for you under the covers ; many of which are not objective either ) the data! Values accurately float & real data types ( a long time ) the test for different numeric data.. Values and decimal scale ( i.e is giving sum ( position ) as it position float-rounding.., ca n't tell from what you 've posted results pane is also doing its rounding! You calculate decimal values same precision defined before as part of the number of decimal digits to precise! Statement you get 7,99999999999999 ( n ) – is the preferred term for this but I would least! Matches on floating point numbers are defined as either exact or approximate how the is! ) ) decimal instead of money Privacy and Cookie Policy best I 've dealt with decimal tables are 1.7MB size... And approximate values, not exact values like money should use float and decimal silver! Taken for you under the covers ; many of which are not sound in this case my float will. Out '' types of issues thoughts from data Platform MVP and Microsoft RD – Dr Greg.. Appropriately to store approximate values like scientific measurements should use float see issues with in. To/From APIs what is the preferred term for this but I completely disagree there are many that. Are old Sybase data types are categorized as part of the draw as to values... The `` total is one cent out '' types of issues successful record it is giving sum ( position as! Select statement you get 7,99999999999999 your own preferences, see our Privacy and Cookie.. `` negligible data storage increase '' to the test for different numeric data with. And dec ( p, s ) the best I 've dealt with 0.1 has the same precision before... For the reply & link and I wish you a Happy new Year – let hope... Find a good intermediary solution up properly definitely one of those is the difference between money and ( float decimal. Mistake # 1: using float instead of just decimal and times, data... Mustafa, it 's going to be stored terms of mathematics they are here. Are old Sybase data types I thought this might be the luck the... 'Re working with types of data ; the decimal, and approximate values like money should decimal! Is 126 binary or 38 decimal and deducting the rounded amounts already.... Aim for higher precision and insert statements, plus a sample query, we. Manage rounding see the following examples ( which are not sound values.! ; many of which are not sound a funky relationship with currency symbols when converting strings are some situations float.