float and real (Transact-SQL)
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.
Note
The SQL-92 synonym for real is float(24).
Data type | Range | Storage |
---|---|---|
float |
- 1.79E+308 to -2.23E-308, 0 and 2.23E-308 to 1.79E+308 |
Depends on the value of n |
real |
- 3.40E + 38 to -1.18E - 38, 0 and 1.18E - 38 to 3.40E + 38 |
4 Bytes |
Transact-SQL Syntax Conventions
Syntax
float [ (n) ]
Where n is the number of bits that are used to store the mantissa of the float number in scientific notation and, therefore, dictates the precision and storage size. If n is specified, it must be a value between 1 and 53. The default value of n is 53.nvalue Precision Storage size 1-24
7 digits
4 bytes
25-53
15 digits
8 bytes
Note
SQL Server 2005 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.
The SQL Server float[(n)] data type complies with the SQL-92 standard for all values of n from 1 through 53. The synonym for double precision is float(53).
See Also
Reference
ALTER TABLE (Transact-SQL)
CAST and CONVERT (Transact-SQL)
CREATE TABLE (Transact-SQL)
Data Types (Transact-SQL)
DECLARE @local_variable (Transact-SQL)
DELETE (Transact-SQL)
INSERT (Transact-SQL)
SET @local_variable (Transact-SQL)
UPDATE (Transact-SQL)
Other Resources
Data Type Conversion (Database Engine)