TSQL Please avoid Float / Real datatypes

The Float / Real (=> Float(24)) datatype are Approximate-number data types. This means you can run into trouble converting them to other type or doing math with them:

From the documentation:

Approximate-number data types for use with floating point numeric data. Floating point data is approximate; therefore, not all values in the data type range can be represented exactly.

(see: http://msdn.microsoft.com/en-us/library/ms173773(v=sql.110).aspx)

Converting example:

DECLARE @f as Float = '29545428.022495';
select cast(@f as numeric(28,14));

result:

29545428.02249500200000

Math Example:

DECLARE @f as Float = '29545428.022495';

select cast(((@f * 4))as numeric(28,14)) ;

118181712.08998001000000

result:
select cast(@f as numeric(28,14)) * 4 ;

result:

118181712.08998000800000

Till Next Time