What does the declaration of the Where method look like when using IQueryable in C#?

The Where method when used with IQueryable in C# is declared as an extension method and takes a predicate expression (a function returning bool) as a parameter. Its signature roughly looks like this:

public static IQueryable<TSource> Where<TSource>(this IQueryable<TSource> source, Expression<Func<TSource, bool>> predicate)

Example of usage:

IQueryable<User> users = dbContext.Users;
var adults = users.Where(u => u.Age >= 18);

Here, predicate is an expression that will be converted into an SQL query during execution, allowing efficient filtering of data on the database side.