8.2. Monetary Types #
The money
type stores a currency amount with a fixed fractional precision; see Table 8.3. The fractional precision is determined by the database's lc_monetary setting. The range shown in the table assumes there are two fractional digits. Input is accepted in a variety of formats, including integer and floating-point literals, as well as typical currency formatting, such as '$1,000.00'
. Output is generally in the latter form but depends on the locale.
Table 8.3. Monetary Types
Name | Storage Size | Description | Range |
---|---|---|---|
money | 8 bytes | currency amount | -92233720368547758.08 to +92233720368547758.07 |
Since the output of this data type is locale-sensitive, it might not work to load money
data into a database that has a different setting of lc_monetary
. To avoid problems, before restoring a dump into a new database make sure lc_monetary
has the same or equivalent value as in the database that was dumped.
Values of the numeric
, int
, and bigint
data types can be cast to money
. Conversion from the real
and double precision
data types can be done by casting to numeric
first, for example:
SELECT '12.34'::float8::numeric::money;
However, this is not recommended. Floating point numbers should not be used to handle money due to the potential for rounding errors.
A money
value can be cast to numeric
without loss of precision. Conversion to other types could potentially lose precision, and must also be done in two stages:
SELECT '52093.89'::money::numeric::float8;
Division of a money
value by an integer value is performed with truncation of the fractional part towards zero. To get a rounded result, divide by a floating-point value, or cast the money
value to numeric
before dividing and back to money
afterwards. (The latter is preferable to avoid risking precision loss.) When a money
value is divided by another money
value, the result is double precision
(i.e., a pure number, not money); the currency units cancel each other out in the division.