SQL：如何使用SUMS（）计算百分比

Question

I'm trying to calculate percentages using SUM() to gather totals.

CONVERT(decimal(10,2), SUM(cola)/(SUM(cola)+SUM(colb)))

I've checked and SUM(cola) = 3 and SUM(colb) = 2; So I was expecting it to calculate like...

3/5 = .6; So I was hoping to get returned, 0.60,

Here's the full query:

    SELECT CASE WHEN this < 0 THEN '-'
                ELSE '+' END AS 'Col1',
                SUM(cola) as 'this', SUM(colb) as 'that',
                CONVERT(decimal(10,2), SUM(cola)/(SUM(cola)+SUM(colb)) as 'PCT'
     FROM Table1
    WHERE colc = 'Condition'
 GROUP BY CASE WHEN this < 0 THEN '-'
               ELSE '+' END

Answer 1

You are doing Integer division .

You need at least one operand to be a float type if you want a float result.

Answer 2

Thanks @Oded, (forgot to convert integers to decimal) So, this is what I changed...

SELECT CASE WHEN this < 0 THEN '-' 
                ELSE '+' END AS 'Col1', 
                SUM(cola) as 'this', SUM(colb) as 'that', 
                CONVERT(decimal(10,2), SUM(cola)/(CONVERT(decimal(10,2),
                SUM(cola))+CONVERT(decimal(10,2), SUM(colb))) as 'PCT' 
     FROM Table1 
    WHERE colc = 'Condition' 
 GROUP BY CASE WHEN this < 0 THEN '-' 
               ELSE '+' END