How to replace Take(1) from Linq query-CodePudding

In a project I have to maintain, I have this Linq query using Take(1) :

(from workflow in db.Workflows
from search in db.Searches.Where(p => p.WorkflowId == workflow.WorkflowId).Take(1).DefaultIfEmpty()
select new { workflow, hasSearch = search.SearchId > 0 }).ToList();

When Take(1) is translated to SQL, it gives something like :

ROW_NUMBER() OVER(PARTITION BY WorkflowId ORDER BY WorkflowId)

which occurs to be lacking performance.

I guess the developer had a SELECT TOP 1 in mind. But if use FirstOrDefault it would not return an IQueryable anymore. So, my question is : how can I rewrite the Linq query to keep the same purpose and not using Take, if possible ?

CodePudding user response：

If understand correctly needed result, query should be rewritten in this way:

var query =
    from workflow in db.Workflows
    select new 
    { 
        workflow, 
        hasSearch = db.Searches.Any(p => p.WorkflowId == workflow.WorkflowId)
    };