如何从MySQL查询结果追加“十进制”在Python

Question

我使用下面的代码运行在Python MySQL查询：

cur = conn.cursor() 
query = ("""select sum(if(grade is not null,1,0)) as `test`, 
    sum(if(grade < 7,1,0)) as `bad`, 
    sum(if(grade < 7,1,0))/sum(if(grade is not null,1,0))*100 as `Pct Bad Grade`, 
    student 
    from grades_database 
    where test_date >= '2014-08-01' 
    group by student 
    order by `Pct Bad Grade` desc;""") 
cur.execute(query) 

，我得到的结果类似

(Decimal('1'), Decimal('3'), Decimal('50.0000'), 'John Doe') 

我需要删除值前面的“Decimal”字符串。

我试图使用从Past Example

output = [] 
for row in cur: 
    output.append(float(row[0])) 
print output 

以下，但它给了我这个

[20.0, 5.0, 3.0, 7.0, 7.0, 2.0, 6.0, 7.0, 7.0, 7.0,...] 

理想情况下，我想重新排列的顺序输出，并得到类似

(John Doe, 50, 3, 1)] 

from

(Decimal('1'), Decimal('3'), Decimal('50.0000'), 'John Doe') 

Answer 1

更改您的查询的顺序，以获得您想要的顺序（名称，然后等级）

cur = conn.cursor() 
query = ("""select student, 
    sum(if(grade is not null,1,0)) as `test`, 
    sum(if(grade < 7,1,0)) as `bad`, 
    sum(if(grade < 7,1,0))/sum(if(grade is not null,1,0))*100 as `Pct Bad Grade` 
    from grades_database 
    where test_date >= '2014-08-01' 
    group by student 
    order by `Pct Bad Grade` desc;""") 
cur.execute(query) 

然后，您可以更改这些值小数点，所以跳过第一个索引（名称）。

for index, row in enumerate(cur): 
    if index: 
     output[index] = int(row) 
print output