convert C# Linq to T-Sql

Question

i'm a junior developer and trying to convert the following linq statement to T-Sql:

    var results = context
      .Employees
      .Where(item => (dateFilter.ToUpper() == "P") ? item.PublishedDate >= From : item.CapturedDate >= dateFromDT)
      .Where(item => (dateFilter.ToUpper() == "P") ? item.PublishedDate <= dateTo : item.CapturedDate <= dateTo)
      .FirstOrDefault()

Can one please help me?

Select * from Employees where PublishedDate = From and .......

Answer 1

I think it should be like this.

 Select Top 1 * from Employees 
     where 
(dateFilter = "P" COLLATE Latin1_General_CS_AS  AND PublishedDate >= From AND PublishedDate >=dateTo) 
OR 
(dateFilter != "P" COLLATE Latin1_General_CS_AS AND CapturedDate  >= dateFromDT AND CapturedDate  >= dateTo)

Answer 2

You could use something similar to this:

select top 1 * 
  from employees 
 where (upper(DateFilter) = 'P' and PublishedDate >= From and PublishedDate <= dateTo)
    or (upper(DateFilter) <> 'P' and CapturedDate >= dateFromDT and CapturedDate <= dateTo)

if DateFilter is a column in the table then it is better to skip the upper as it can degrade performance (given that you have a index on that column).