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.
.gif) Note: |
|---|
|
The ISO 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
|
.gif)
Transact-SQL Syntax Conventions
-
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.
|
n
value
|
Precision
|
Storage size
|
|---|
|
1-24
|
7 digits
|
4 bytes
|
|
25-53
|
15 digits
|
8 bytes
|
| Note: |
|---|
|
SQL Server 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 ISO standard for all values of n from 1 through 53. The synonym for double precision is float(53).
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)
Help and Information
Getting SQL Server 2008 Assistance