问题
I am trying to save a float number which is this long
13.00386644742523
Its basically Lat and Lng value. when i save it in the database its getting stored as
13.0039
回答1:
Based on experience I did this for a navigation database built from ARINC424 and eventually used a DECIMAL(18,12) for storing values in radians.
NOTE: Floats and doubles aren't as precise and may result in rounding errors
The point is that when using degrees or radians we know the range of the values - and the fractional part needs the most digits.
The best way is to use MySQL Spatial Extensions
回答2:
You should use the precision explicitly and the type should be DECIMAL NOT FLOAT
as every digit after decimal point is significant and you cant let they allow to be changed because of rounding.
`lat` DECIMAL(16,14)
Read on manual
回答3:
I think your data type for the the column is defined as Float(N,4) where N is the number and 4 is the number of decimal places allowed. That is why it is rounding the stored value.
The best way to store Lat/Long is to use spatial data type. POINT geometry type will hold your values
来源：https://stackoverflow.com/questions/11185997/mysql-storing-floats