我用sqlalchemy创建了一个临时表（具有基础的postgres数据库），该表将与数据库表连接。但是，在某些情况下，如果值''为空，则postgres会引发错误：
failed to find conversion function from unknown to text
SqlAlchemy将所有内容组装到以下上下文中
[SQL: 'WITH temp_table AS \n(SELECT %(param_1)s AS id, %(param_2)s AS email, %(param_3)s AS phone)\n SELECT campaigns_contact.id, campaigns_contact.email, campaigns_contact.phone \nFROM campaigns_contact JOIN temp_table ON temp_table.id = campaigns_contact.id AND temp_table.email = campaigns_contact.email AND temp_table.phone = campaigns_contact.phone'] [parameters: {'param_1': 83, 'param_2': '', 'param_3': '+1234567890'}]
我按照以下步骤组装临时表
stmts = []
for row in import_data:
row_values = [literal(row[value]).label(value) for value in values]
stmts.append(select(row_values))
subquery = union_all(*stmts)
subquery = subquery.cte(name="temp_table")
问题似乎出在这里
...%(param_2)s AS email...
替换param_2后会导致
...'' AS email...
这将导致上述错误。 解决该问题的一种方法是执行强制转换
...''::text AS email...
但是，我不知道如何使用sqlalchemy执行::text强制转换！？