float and real
Approximate number data types for use with floating point numeric data. Floating point data is approximate; not all values in the data type range can be precisely represented.
float [ ( n ) ]
Is a floating point number data with the following valid values: - 1.79E + 308 through -2.23E - 308, 0 and 2.23E -308 through 1.79E + 308. n is the number of bits used to store the mantissa of the float number in scientific notation and thus dictates the precision and storage size. n must be a value from 1 through 53. The default value of n is 53.
|n is||Precision||Storage size|
|1-24||7 digits||4 bytes|
|25-53||15 digits||8 bytes|
The Microsoft® SQL Server™ float[(n)] data type conforms to the SQL-92 standard for all values of n from 1 to 53. The synonym for double precision is float(53).
Is a floating point number data with the following valid values: –3.40E + 38 through -1.18E - 38, 0 and 1.18E - 38 through 3.40E + 38. Storage size is 4 bytes. In SQL Server, the synonym for real is float(24).
Note Microsoft® SQL Server™ 2000 treats n as one of two possible values. If 1<=n<=24, n is treated as 24. If 25<=n<=53, n is treated as 53.