如何写不等于运营商在LINQ to SQL的？ [英] How to write not equal operator in linq to sql?

问题描述

using (RapidWorkflowDataContext context = new RapidWorkflowDataContext())
                    {
                        var query = from w in context.WorkflowInstances
                        from c in context.Workflows 
                         where EmpWorkflowIDs.Contains((int)w.ID) && w.CurrentStateID != c.LastStateID
                         select w;

                        return query.ToList();
                    }

我有2表：工作流和WorkflowInstances

I have 2 tables: Workflows and WorkflowInstances.

工作流程来存储对象和workflowInstances存储实例

Workflows to store objects and workflowInstances to store instances.

工作流表：ID，名称，FirstStateID，LastStateID

Workflows Table: ID,Name,FirstStateID,LastStateID

WorkflowInstances表：ID，名称，WorkflowID，CurrentStateID

WorkflowInstances Table: ID,Name,WorkflowID,CurrentStateID

如何写在LINQ查询到SQL来选择从哪个CurrentStateID WorkflowInstances实例不等于LastStateID

How to write a query in linq to sql to select the instances from WorkflowInstances which CurrentStateID not equal LastStateID

推荐答案

您需要修改的连接要对两个表之间的相关列，那么你添加的条件WHERE子句中，像下面的：

You need to revise the join to be on the related columns between the 2 tables, then you add your condition in the where clause, like the following:

using (RapidWorkflowDataContext context = new RapidWorkflowDataContext())
                        {
                            var query = from w in context.WorkflowInstances
                                        join c in context.Workflows on w.WorkflowID equals c.ID
                                         where EmpWorkflowIDs.Contains((int)w.ID)
                                         && w.CurrentStateID != c.LastStateID
                                         select w;

                            return query.ToList();
                        }

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