Range, Precision, and Storage Size

The real and double precision types are built on types supplied by the operating system. The float type accepts an optional binary precision in parentheses. float columns with a precision of 1–15 are stored as real; those with higher precision are stored as double precision.

The range and storage precision for all three types is machine-dependent.

The range and storage size for each approximate numeric type are:


Bytes of Storage

float[(default precision)]

4 for default precision < 16

8 for default precision >= 16

double precision




isql displays only 6 significant digits after the decimal point and rounds the remainder.