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我正在使用 simple_history，因为我需要模型的历史数据。我有一个名为 po_staff 的模型，它有一个名为 pool_historicalpo_staff 的“历史”模型。现在我想获得一个基于 pool_historicalpo_staff 的查询集，其中包含每个员工的最后一条记录（我试图使其尽可能简单，因为真正的查询要复杂得多）。我目前正在使用 SQLLite

历史模型包含以下数据：

ID staff_nr valid      staff_firstname staff_lastname
1  111      01/01/2014 Firstname1      Lastname1
2  3        01/01/2014 Firstname2      Lastname2
2  3        01/04/2014 Firstname2      Lastname2_new #Employee has changed his Lastname

此代码工作正常（按字母顺序排列）：

qs = po_staff.history.raw ('SELECT * FROM pool_historicalpo_staff '
     'WHERE clientID_id is %s and companyID_id is %s '
     'GROUP BY id '
     'ORDER BY staff_name, staff_surname ',
     [client_id, company_id])

我必须使用“id”进行分组，因为可以从用户更改staff_nr（但它仍然是同一个员工）。

问题1：用户可以在alpabetical和staff_id之间选择结果的顺序

为了使这成为可能，我在查询中添加了第三个参数：

if order == 1:
    order_by = "staff_name, staff_surname"
else:
    order_by = "staff_nr"
qs = po_staff.history.raw ('SELECT * FROM pool_historicalpo_staff '
     'WHERE clientID_id is %s and companyID_id is %s '
     'GROUP BY id '
     'ORDER BY %s ',
     [client_id, company_id, order_by])

查询有效，但不是按字母顺序，而是按“id”排序。

问题 2：也必须为其他模型执行查询。只是模型和 order_by 会有所不同。我不想为每个模型编写几乎相同的查询，因此我尝试使其更灵活：

model      = ....  # instance of current model
order_by   = ....  # gets the choosen order for current model, p.e. "staff_name, staff_surname"
model_name = ....  # gets the model name, p.e. "pool_historicalpo_staff"

qs = model.history.raw ('SELECT * FROM %s '
     'WHERE clientID_id is %s and companyID_id is %s '
     'GROUP BY id '
     'ORDER BY %s ',
     [model_name, client_id, company_id, order_by])

执行此查询时出现错误：

Request Method:     GET
Request URL:    http://127.0.0.1:8000/framework/21/?view=kanban
Django Version:     1.7
Exception Type:     OperationalError
Exception Value:    near "?": syntax error
Exception Location:     c:\python34\lib\site-packages\django\db\backends\sqlite3\base.py in     
                        execute, line 485
Python Executable:  c:\python34\python.EXE
Python Version:     3.4.0

我希望我清楚地解释了一切。我是 django 的新手，这是我的第一个原始 SQL

非常感谢您的帮助！

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1 回答 1

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This seems similar to Django: MySQL syntax error when passing parameters to raw SQL query

Short answer: you can only pass parameters to the query. To support substituting parts of the SQL syntax like table names, you will need to build the query in two passes, only passing the actual parameters to the query in the second pass.

Hope this helps.

于 2015-01-11T13:29:11.000 回答