How to calculate the percentage of a column in mysql

I have a table with some number fields an开发者_运维问答d I want to get calculate the percentage of each value in that field. Which means I want to get the sum of the column and divide by it the every row and to multiply by 100. But it doesn't work. Can u help me?

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Like this?

select OrderQty * 100.0 / (select sum(OrderQty) from SalesOrderDetail)
from SalesOrderDetail