python - Pyodbc + sqlalchemy 超过 2100 个项目失败

Question

在下面的代码中，当employee_code_list 长于2000 项时会引发错误，如下所述。但是，当列表少于 2000 个项目时，它可以完美运行。

query = session.query(TblUserEmployee, TblUser).filter(
                and_(
                    (TblUser.UserId == TblUserEmployee.EmployeeId),
 (func.lower(TblUserEmployee.EmployeeCode).in_(employee_code_list)),
                    (TblUser.OrgnId == MIG_CONSTANTS.context.organizationid),
                    (TblUser.UserTypeId == user_type)
                ))

            results = query.all()

这是引发的错误的相关部分：

File ""site-packages\sqlalchemy\util\compat.py"", line 203, in raise_from_cause
  File ""site-packages\sqlalchemy\engine\base.py"", line 1193, in _execute_context
  File ""site-packages\sqlalchemy\engine\default.py"", line 507, in do_execute
DBAPIError: (pyodbc.Error) ('07002', u'[07002] [Microsoft][ODBC Driver 17 for SQL Server]COUNT field incorrect or syntax error (0) (SQLExecDirectW)') [SQL: u'SELECT [tblTaxGroup].[TaxGroupId] AS [tblTaxGroup_TaxGroupId], [tblTaxGroup].[Code] AS [tblTaxGroup_Code], [tblTaxGroupCenter].[CenterId] AS [tblTaxGroupCenter_CenterId] \nFROM [tblTaxGroup], [tblTaxGroupCenter], [tblCenterTax] \nWHERE [tblTaxGroup].[OrganizationId] = ? AND [tblTaxGroup].[Void] = 0 AND [tblTaxGroup].[TaxGroupId] = [tblTaxGroupCenter].[TaxGroupId] AND [tblTaxGroup].[Code] IN (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, 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?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, 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?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?) AND [tblCenterTax].[CenterId] = [tblTaxGroupCenter].[CenterId] AND [tblCenterTax].[TaxGroupId] = [tblTaxGroupCenter].[TaxGroupId] AND [tblCenterTax].[ApplyToVendors] = 1 AND [tblTaxGroupCenter].[Void] = 0'] [parameters: (u'A8D7DD91-152D-4042-8205-8EEB1DB2A283', u'SGST18', u'SGST18', u'SGST18', u'SGST18', u'SGST18', u'SGST18', u'SGST18', u'SGST18', u'SGST18', u'SGST18', u'SGST18', u'SGST18', u'SGST18', u'SGST18', u'SGST18', u'SGST18', u'SGST18', u'SGST18', u'SGST18', u'SGST18', u'SGST18', u'SGST18', u'SGST18', u'SGST18', u'SGST18', u'SGST18', u'SGST18', u'SGST18', u'SGST18', u'SGST18', u'SGST18', u'SGST18', u'SGST18', u'SGST18', u'SGST18', .......u'SGST18')] (Background on this error at: http://sqlalche.me/e/dbapi)

这是我正在使用的连接器：

 engine_meta = create_engine(
                'mssql+pyodbc://' +
                global_json["target_database_username"] + ':' +
                global_json["target_database_password"] + '@' +
                global_json["target_database_server_ip"] + "/" +
                global_json["target_database_name"],
                implicit_returning=False)

由于其他一些原因，我们最近将连接器从 pymssql 更改为 pyodbc。当我们使用 pymssql 时没有出现这个问题

编辑：复制了更多的错误信息。已将其裁剪，因为它显示了我的组织数据库的详细信息。而且由于相同的查询适用于较少数量的项目，我确信这不是语法错误。注意：错误不是由于相同的值被替换，也尝试过所有唯一值的情况，仍然有相同的错误。

标签： pythonsqlalchemypyodbc

Answer 1

您的查询基本上是在强制 SQLAlchemy 发出带有 2000 多个参数的查询（SELECT * WHERE Y IN (list of 2000+ values)）。不同的 RDBMS（和不同的驱动程序）对您可能拥有的参数数量有限制。

尽管您的堆栈跟踪没有涵盖确切的错误，但我注意到您正在使用 SQL Server，并且您正在谈论的数字可疑地接近 SQL Server 在某些情况下施加的 2100 参数限制（请参阅每个用户定义的参数此Microsoft 知识文章中的功能）。我愿意打赌这就是你遇到的。

您可以采取的最简单的方法是简单地为每个例如 1000 个项目分批运行查询employee_code_list：

results = []
batch_size = 1000
batch_start = 0

while batch_start < len(employee_code_list):
    batch_end = batch_start + batch_size
    employee_code_batch = employee_code_list[batch_start:batch_end]
    query = session.query(TblUserEmployee, TblUser).filter(
                and_(
                    (TblUser.UserId == TblUserEmployee.EmployeeId),
                    (func.lower(TblUserEmployee.EmployeeCode).in_(employee_code_batch)),
                    (TblUser.OrgnId == MIG_CONSTANTS.context.organizationid),
                    (TblUser.UserTypeId == user_type)
                ))
    results.append(query.all())
    batch_start += batch_size

在此示例中，我们将创建一个空的结果列表，我们会将每批结果附加到该列表中。我们将批量大小设置为 1000，起始位置为 0（中的第一项employee_code_list）。然后，我们针对每批 1000 条运行您的查询，并将结果附加到 中results，直到没有任何记录可供查询employee_code_list。

当然还有其他方法，但这种方法不需要您使用不同的 RDBMS，并且可能最容易在您的代码中使用。