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[英]Why is peewee including the 'id' column into the mysql select query?
[英]Why peewee coerces select column to integer
我不能在peewee中使用sqlite函數group_concat()。 這是完整的片段。 peewee希望以某種方式將group_concat()的結果轉換為整數(字符串(“ 1,2”))。 我找不到抑制它的方法。
from peewee import *
db = SqliteDatabase(':memory:')
class Test(Model):
name = CharField()
score = IntegerField()
class Meta:
database = db
db.create_tables([Test])
Test.create(name='A', score=1).save()
Test.create(name='A', score=2).save()
#select name, group_concat(score) from Test group by name
for t in Test.select(Test.name, fn.group_concat(Test.score)).order_by(Test.name):
pass
它產生以下錯誤:
Traceback (most recent call last):
File "C:\Users\u_tem0m\Dropbox\Wrk\sgo\broken.py", line 17, in <module>
for t in Test.select(Test.name, fn.group_concat(Test.score)).order_by(Test.name):
File "C:\Program Files\Python 3.5\lib\site-packages\peewee.py", line 1938, in next
obj = self.qrw.iterate()
File "C:\Program Files\Python 3.5\lib\site-packages\peewee.py", line 1995, in iterate
return self.process_row(row)
File "C:\Program Files\Python 3.5\lib\site-packages\peewee.py", line 2070, in process_row
setattr(instance, column, func(row[i]))
File "C:\Program Files\Python 3.5\lib\site-packages\peewee.py", line 874, in python_value
return value if value is None else self.coerce(value)
ValueError: invalid literal for int() with base 10: '1,2'
嘗試在對group_concat的調用中添加一個coerce(False)
:
query = (Test
.select(Test.name, fn.GROUP_CONCAT(Test.score).coerce(False))
.order_by(Test.name))
for t in query:
pass
Peewee看到Test.score是一個整數字段,因此無論何時在該列上調用函數,Peewee都會嘗試將結果轉換回int。 問題是group_concat返回一個字符串,因此我們必須告訴Peewee不要弄亂返回值。
剛剛發現fn.group_concat(“” + Test.score)的結果沒有轉換為整數。 但是我認為生成的sql可能不太理想
選擇“ t1”。“ name”,group_concat(?+“ t1”。“ score”)AS allscore FROM“ test” AS t1 OR BY BY“ t1”。“ name” [“]
有人知道更優雅的方式嗎?
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