What is the precision value of float

The FLOAT data type is used to store a single or double precision floating point number.

If a column with the FLOAT data type ( precision ) is created, it is guaranteed that the columns on all platforms save the values ​​at least up to the specified minimum total digits. With REAL and DOUBLE, however, no platform-independent minimum total number of digits is guaranteed.

If precision is not specified, the FLOAT data type is a single-precision floating point number, equivalent to the REAL data type, and requires 4 bytes of storage space.

If precision is specified, the FLOAT data type is either single-precision or double-precision, depending on the total number of digits value. The difference between REAL and DOUBLE depends on the platform. Single-precision FLOAT values ​​require 4 bytes of storage space and double-precision FLOAT values ​​require 8 bytes.

The FLOAT data type is an approximate numeric data type. Rounding errors can occur after arithmetic operations. Because FLOAT values ​​are approximate, queries that use equality should generally be avoided when comparing FLOAT values.

See also
Standards and Compatibility