postgresql - Postgres 自定义浮点类型，它总是在点后截断为 2 位小数

Question

我能否在 postgres 中生成一个自定义数据类型，每次我向其中插入或更新一个 float 时，它都会在点后被截断为 2 位小数。

create table money(

   formatted moneys_type
);

insert into money values (30.122323213);

Select * from money; 

返回

30.12

更新我没有使用数字或小数，因为它们在 1.999 => 2 时四舍五入

Answer 1

参见 documentation on Numeric Types / Arbitrary Precision Numbers .

The precision of a numeric is the total count of significant digits inthe whole number, that is, the number of digits to both sides of thedecimal point. The scale of a numeric is the count of decimal digitsin the fractional part, to the right of the decimal point. So thenumber 23.5141 has a precision of 6 and a scale of 4. Integers can beconsidered to have a scale of zero.

...

To declare a column of type numeric use the syntax:

NUMERIC(precision, scale)

The maximum allowed precision when explicitly specified in the type declaration is 1000.

所以你可以使用

NUMERIC(1000, 2)