| Data type | Alias | Size | Range |
|---|---|---|---|
REAL | FLOAT4 | 4 bytes | 6 decimal digits precision |
DOUBLE PRECISION | DOUBLE, FLOAT8, FLOAT [(p)] | 8 bytes | 15 decimal digits precision |
FLOAT(p). When it is being used, the optional p specifies the minimum acceptable precision in binary digits and it can range between 1 to 53. FLOAT(1) to FLOAT(24) as selecting the REAL type, while FLOAT(25) to FLOAT(53) select DOUBLE PRECISION. A value of p outside the allowed range results in an error. The default value is 53 (maximum precision).