我需要使用SQL語句計算得分百分比

Question

目前我得到的輸出爲「25/50」作爲字符串通過SQL，現在我需要從此得分計算百分比，並使用SQL語句返回該值Post Gres SQL。

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

這會返回一個字符串「25/50」。現在我想從這個字符串計算百分比。

Answer 1

需要分割你的數據第一次，那麼你可以計算出百分比... 可以使用

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

我這裏是

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;