Performance of LINQ Any vs FirstOrDefault != null

Question

There are multiple places in an Open Source Project (OSP) code I contribute, where it has to be determined if an element in a collection satisfies a certain condition.

Answer 1

We can use .Count(x => x....) != 0 instead of using .Any(x => x....) or .FirstOrDefault(x => x....) != null

Because query generation of Linq is below,

(In Any(), the 2nd(Not Exists) condition is not need i think.)

.Any(x => x.Col_1 == 'xxx')

    (@p__linq__0 varchar(8000))SELECT 
CASE WHEN ( EXISTS (SELECT 
    1 AS [C1]
    FROM [dbo].[Table_X] AS [Extent1]
    WHERE [Extent1].[Col_1] = @p__linq__0
)) THEN cast(1 as bit) WHEN ( NOT EXISTS (SELECT 
    1 AS [C1]
    FROM [dbo].[Table_X] AS [Extent2]
    WHERE [Extent2].[Col_1] = @p__linq__0
)) THEN cast(0 as bit) END AS [C1]
FROM  ( SELECT 1 AS X ) AS [SingleRowTable1]

.FirstOrDefault(x => x.Col_1 == 'xxx') != null

 (@p__linq__0 varchar(8000))SELECT TOP (1) 
[Extent1].[Col_1] AS [Col_1], 
[Extent1].[Col_2] AS [Col_2], 
...
[Extent1].[Col_n] AS [Col_n]
FROM [dbo].[Table_X] AS [Extent1]
WHERE [Extent1].[Col_1] = @p__linq__0

.Count(x => x.Col_1 == 'xxx') != 0

  (@p__linq__0 varchar(8000))SELECT 
[GroupBy1].[A1] AS [C1]
FROM ( SELECT 
    COUNT(1) AS [A1]
    FROM [dbo].[Table_X] AS [Extent1]
    WHERE [Extent1].[Col_1] = @p__linq__0
)  AS [GroupBy1]