我需要使用SQL语句计算得分百分比

Question

目前我得到的输出为“25/50”作为字符串通过SQL，现在我需要从此得分计算百分比，并使用SQL语句返回该值Post Gres SQL。

SELECT es.score FROM emp_scores es WHERE id = 123; 

这会返回一个字符串“25/50”。现在我想从这个字符串计算百分比。

Answer 1

需要分割你的数据第一次，那么你可以计算出百分比... 可以使用

split_part(string text, delimiter text, field int) 
    //Split string on delimiter and return the given field (counting from one) 

我这里是

SELECT (CAST(coalesce(split_part(es.score,'/',2)*100), '0') AS integer)*100)/CAST(coalesce(split_part(es.score,'/',1)*100), '0') AS integer) as 'Percentage' FROM emp_scores es WHERE id = 123; 

Answer 2

select 
cast(substring(es.score,0,patindex('%/%',es.score)) as int)/ 
cast(substring(es.score 
     ,patindex('%/%',es.score)+1 
     ,len(es.score)-patindex('%/%',es.score)) as int)*100 
FROM emp_scores es WHERE id = 123; 

Answer 3

又如使用CTE

create table emp_scores (
    gid serial primary key, 
    score varchar 
); 
insert into emp_scores values (123, ' 25/50 '); 

with t as (
    select regexp_split_to_array(' 25/50 ', '/') scores from emp_scores where gid = 123 
) 
select 100 * scores[1]::real/scores[2]::real from t;