To ensure that you get a decimal value when performing your calculations in SQL, you need to make sure that the division operation involves decimal types rather than integers. If any part of the operation involves integers, SQL will perform integer division, which will truncate any decimal portion and result in a whole number.

Solution :

First, Convert your integers to decimal before the division operation. This ensures that SQL treats the division as a decimal operation.

declare @percents decimal(16,2) = convert(decimal(16,2), 100);

declare @fifteenPercentage decimal(16,2) = 
    (convert(decimal(16,2), @fifteen) / convert(decimal(16,2), @total)) * @percents;

select '1-15: (' + trim(str(@fifteen)) + ') ' + trim(str(@fifteenPercentage)) + '%' as ratingB;

By converting @fifteen and @total to decimal(16,2) before performing the multiplication and division, SQL will handle the entire operation in decimal format, preserving the decimal part in the result.

The convert(decimal(16,2), @total) ensures that even if @total is zero, you would get a division error or a specific message instead of the entire operation resulting in an integer.