Django在使用python的旧式字符串格式时无法处理sql中的%symbol

Question

我使用的是Django 2.0.5，我的（不可更改的）旧式sqlite数据库在一些列名中有%symbol

CREATE TABLE tbl("name" text, "col1(%)" float);

当我使用django模型过滤器时，过滤器值作为参数应用于sql字符串，其中%operator为：

'SELECT "col1(%)" from tbl where name LIKE "%s" ' % 'John%'

不幸的是，在这种情况下，Django没有转义%符号（在列名中），这导致字符串格式选项出错

有什么建议可以解决这个问题吗

编辑：我想我的问题是关于https://code.djangoproject.com/ticket/9055， 问题只出现在Django调试模式下

以下是回溯：

Traceback (most recent call last):
  File "C:\svn\br_sqlite\camp2\venv\lib\site-packages\django\core\handlers\exception.py", line 35, in inner
    response = get_response(request)
  File "C:\svn\br_sqlite\camp2\venv\lib\site-packages\django\core\handlers\base.py", line 128, in _get_response
    response = self.process_exception_by_middleware(e, request)
  File "C:\svn\br_sqlite\camp2\venv\lib\site-packages\django\core\handlers\base.py", line 126, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "C:\svn\br_sqlite\camp2\main\views.py", line 72, in showData
    qs = validateInput(model,batch,version)
  File "C:\svn\br_sqlite\camp2\main\views.py", line 36, in validateInput
    return qs if len(qs) > 0 else None
  File "C:\svn\br_sqlite\camp2\venv\lib\site-packages\django\db\models\query.py", line 254, in __len__
    self._fetch_all()
  File "C:\svn\br_sqlite\camp2\venv\lib\site-packages\django\db\models\query.py", line 1179, in _fetch_all
    self._result_cache = list(self._iterable_class(self))
  File "C:\svn\br_sqlite\camp2\venv\lib\site-packages\django\db\models\query.py", line 53, in __iter__
    results = compiler.execute_sql(chunked_fetch=self.chunked_fetch, chunk_size=self.chunk_size)
  File "C:\svn\br_sqlite\camp2\venv\lib\site-packages\django\db\models\sql\compiler.py", line 1066, in execute_sql
    cursor.execute(sql, params)
  File "C:\svn\br_sqlite\camp2\venv\lib\site-packages\django\db\backends\utils.py", line 104, in execute
    sql = self.db.ops.last_executed_query(self.cursor, sql, params)
  File "C:\svn\br_sqlite\camp2\venv\lib\site-packages\django\db\backends\sqlite3\operations.py", line 143, in last_executed_query
    print(sql % params)
ValueError: unsupported format character ')' (0x29) at index 3252

示例模型：

class tbl(models.Model):
    name=models.TextField()
    col1=models.TextField(db_column="col1(%)")

和一个视图：

def test(request):
    a = tbl.objects.filter(name__contains='ab')
    return ""

Answer 1

尝试使用

'SELECT "col1(%%)" from tbl where name LIKE "%s" ' % 'John%'

将Double%%转义为单1