Question

我使用以下代码在Python中运行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)

我得到了类似

的结果

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

我需要删除值前面的“Decimal”字符串。

我尝试使用Past Example

中的以下内容

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

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，我想重新排列输出的顺序，并获得类似

的内容

(John Doe, 50, 3, 1)]

来自

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

Answer 1

更改查询的顺序以获得所需的订单（名称然后成绩）

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)

然后您可以更改十进制值，因此请跳过第一个索引（名称）。

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

如何在Python中从MySQL查询结果中附加“Decimal”

1 个答案: