将 SQLAlchemyliteral
与date
对象一起使用时,会引发异常。
演示
# Versions used:
# databases 0.4.1
# asyncpg 0.21.0
# SQLAlchemy 1.3.20
import asyncio
from datetime import date
from databases import Database
from sqlalchemy import select, literal
database = Database('postgresql://user:password@localhost/dbname')
async def run():
await database.connect()
today = date.today()
query = select([
literal(today).label('today') # <-- The problem is here
])
await database.fetch_all(query)
await database.disconnect()
loop = asyncio.get_event_loop()
loop.run_until_complete(run())
例外
Traceback (most recent call last):
File "test.py", line 21, in <module>
loop.run_until_complete(run())
File "C:\Python38\lib\asyncio\base_events.py", line 616, in run_until_complete
return future.result()
File "test.py", line 14, in run
rows = await database.fetch_all(query)
File "C:\Python38\lib\site-packages\databases\core.py", line 140, in fetch_all
return await connection.fetch_all(query, values)
File "C:\Python38\lib\site-packages\databases\core.py", line 239, in fetch_all
return await self._connection.fetch_all(built_query)
File "C:\Python38\lib\site-packages\databases\backends\postgres.py", line 160, in fetch_all
rows = await self._connection.fetch(query, *args)
File "C:\Python38\lib\site-packages\asyncpg\connection.py", line 443, in fetch
return await self._execute(query, args, 0, timeout)
File "C:\Python38\lib\site-packages\asyncpg\connection.py", line 1445, in _execute
result, _ = await self.__execute(
File "C:\Python38\lib\site-packages\asyncpg\connection.py", line 1454, in __execute
return await self._do_execute(query, executor, timeout)
File "C:\Python38\lib\site-packages\asyncpg\connection.py", line 1476, in _do_execute
result = await executor(stmt, None)
File "asyncpg\protocol\protocol.pyx", line 178, in bind_execute
File "asyncpg\protocol\prepared_stmt.pyx", line 160, in asyncpg.protocol.protocol.PreparedStatementState._encode_bind_msg
asyncpg.exceptions.DataError: invalid input for query argument $1: datetime.date(2020, 11, 30) (expected str, got date)
为什么它期待一个str?
编辑
它适用于 MySQL,所以我的猜测是问题出在asyncpg中。