mysql - 如何使用SQL插入小数点和四舍五入

Question

数据集来自https://sqlzoo.net/wiki/SELECT_from_WORLD_Tutorial ，数字 9

我正在使用

SELECT name, ROUND(population, 3,0), ROUND(GDP, 3,0)
FROM world
WHERE continent = 'South America' 

答案应该是

name        
Argentina   42.67   477.03
Bolivia 10.03   27.04
Brazil  202.79  2254.11

我正在获取

name        
Argentina   42669500    477028000000
Bolivia 10027254    27035000000
Brazil  202794000   2254109000000

...

Answer 1

您希望人口以百万为单位，GDP 以十亿为单位，四舍五入到小数点后两位。考虑:

SELECT name, ROUND(population/1000000, 2), ROUND(GDP/1000000000, 2)
FROM world
WHERE continent = 'South America'