Pyodbc + sqlalchemy 超过 2100 个项目失败

Question

在下面的代码中，当 employee_code_list 超过 2000 项时会抛出错误，如下所述。但是，当列表少于 2000 项时，它会完美运行。

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()

这是抛出错误的相关部分：

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)

我们最近出于某些其他原因将连接器从 pymssql 更改为 pyodbc。当我们使用 pymssql

时，这个问题不存在

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。由于相同的查询适用于较少数量的项目，因此我确信这不是语法错误。注意：错误不是由于替换了相同的值，也尝试了所有唯一值的情况，仍然有相同的错误。

Answer 1

您的查询基本上是在迫使 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。

虽然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 服务器，并且您所说的数字可疑地接近 2100 参数限制 SQL 服务器在某些情况下强加（请参阅 this Microsoft 知识文章中的 每个用户定义函数的参数 。我敢打赌，这就是您运行的目标。

您可以采取的最简单的方法是简单地运行分批查询 employee_code_list 中的每个项目，例如 1000 个项目：

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

在这个例子中，我们创建了一个空的结果列表，我们将把每批结果附加到该列表中。我们将批量大小设置为 1000，并将起始位置设置为 0（employee_code_list 中的第一项）。然后我们运行对每批 1000 个进行查询，并将结果附加到 results，直到 employee_code_list.

中没有要查询的记录为止

当然还有其他方法，但这是一种不需要您使用其他 RDBMS 的方法，并且可能最容易融入您的代码。

Pyodbc + sqlalchemy 超过 2100 个项目失败

Pyodbc + sqlalchemy fails for more than 2100 items

python

sqlalchemy

pyodbc