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.
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The ISO synonym for real is float(24).
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Data type
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Range
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Storage
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float
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- 1.79E+308 to -2.23E-308, 0 and 2.23E-308 to 1.79E+308
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Depends on the value of n
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real
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- 3.40E + 38 to -1.18E - 38, 0 and 1.18E - 38 to 3.40E + 38
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4 Bytes
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Transact-SQL Syntax Conventions
Syntax
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float [ ( n ) ]
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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.
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n
value
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Precision
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Storage size
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1-24
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7 digits
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4 bytes
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25-53
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15 digits
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8 bytes
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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.
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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).
See Also