How do you store scientific notation numbers in MySQL

若如初见. 提交于 2019-12-23 12:28:18

问题


I want to store scientific notation numbers in MySql.

I've saved them to a field which has datatype decimal. The issue is that it stores it in normal notation (at least that what it seems when I view the number in the web console that comes with MAMP) and thus you need to allocate more bytes to the field ... which I believe will lead to having a very large database.

Is there anyway to store the scientific notation as is (far fewer units of information), but still be able to do numeric computations e.g. < and > (context for the last comment is that if you just needed to display the value you could store it as a text type, but that won't do for me).


回答1:


FLOAT and DOUBLE datataypes can be shown (and inserted) using Scientific notation:

CREATE TABLE numSC
( f float
, d double
) ;

INSERT INTO numSC
VALUES
(POW(10,30), POW(10,30)) ;

INSERT INTO numSC
VALUES
(10.1234567890123456e-20, 10.1234567890123456e-20) ;

SELECT * FROM numSC ;

>  |         f    |                  d    |
>  |       1e+030 |                1e+030 |
>  | 1.01235e-019 | 1.01234567890123e-019 |



回答2:


Save them in a field of type double.



来源:https://stackoverflow.com/questions/6401145/how-do-you-store-scientific-notation-numbers-in-mysql

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