How do I calculate percentages with decimals in SQL?

问题

How can i convert this to a decimal in SQL? Below is the equation and i get the answer as 78 (integer) but the real answer is 78.6 (with a decimal) so i need to show this as otherwise the report won't tally up to 100%

(100 * [TotalVisit1]/[TotalVisits]) AS Visit1percent

回答1:

convert(decimal(5,2),(100 * convert(float,[TotalVisit1])/convert(float,[TotalVisits]))) AS Visit1percent

Ugly, but it works.

回答2:

Try This:

(100.0 * [TotalVisit1]/[TotalVisits]) AS Visit1percent

回答3:

At least in MySQL (if it helps), if you want to use float numbers you had to use a type float field, not the regular int fields.

回答4:

Just add a decimal to the 100

(100.0 * [TotalVisit1]/[TotalVisits]) AS Visit1percent

this forces all processing to happen in floats... if you want the final output as text, and truncated for display to only one decimal place, use Str function

Str( 100.0 * [TotalVisit1]/[TotalVisits], 4, 1 ) AS Visit1percent

回答5:

CAST(ROUND([TotalVisit1]*100.0/[TotalVisits],2)as decimal(5,2)) as Percentage

Not ugly and work better and fast , enjoy it!

回答6:

Its probably overkill to do this, but you may wish to consider casting all values to floats to ensure accuracy at all phases.

(100.0 * ( [TotalVisit1]+0.0 )/([TotalVisits]+0.0) ) as Visit1percent

Note, you really need to put code in here for the case that TotalVisits == 0 or you will get a division by 0 answer.

回答7:

SELECT(ROUND(CAST(TotalVisit1 AS DECIMAL)/TotalVisits,1)) AS 'Visit1percent'

This will return a decimal and the ROUND will round it to one digit. So in your case you would get 76.6. If you don't want any digits change the 1 to 0 and if you want two digits change it to 2.

回答8:

Try with this, no round and str or Over(). i found this as a simpler way to do it.

cast((count(TotalVisit1) * 100.0) /TotalVisits as numeric(5,3))  as [Visit1percent]

You can change the number of decimal points as you wish to

e.g. numeric(5,2) or numeric(5,4)

回答9:

This might not address you issue directly, but when you round a set of numbers for display you're never guaranteed to get numbers that add to 100 unless you take special precautions. For example, rounding 33.33333, 33.33333 and 33.33333 is going to leave you one short on the sum, so the logical thing to do is to modify the percentage for the largest value in the set to take account of any difference.

Here's a way of doing that in Oracle SQL using analytic functions and a subquery factoring (WITH) clause to generate sample data.

with data as (select 25 num from dual union all
              select 25     from dual union all
              select 25     from dual)
select num, 
case
   when rnk = 1
   then 100 - sum(pct) over (order by rnk desc
                             rows between unbounded preceding
                                      and         1 preceding)
   else pct
end pct
from
   (
   select num,
          round(100*ratio_to_report(num) over ()) pct,
          row_number() over (order by num desc) rnk
   from data
   )
/


NUM                    PCT                    
---------------------- ---------------------- 
25                     33                    
25                     33                     
25                     34

回答10:

In ms Access You can use the SQL function ROUND(number, number of decimals), It will round the number to the given number of decimals:

ROUND((100 * [TotalVisit1]/[TotalVisits]),1) AS Visit1percent

来源：https://stackoverflow.com/questions/400557/how-do-i-calculate-percentages-with-decimals-in-sql

标签

sql

decimal

sum