Entity framework EF.Functions.Like vs string.Contains

Question

I was reading the announcement of entity framework core 2.0 https://blogs.msdn.microsoft.com/dotnet/2017/08/14/announcing-entity-framework-core-2-0/

It says that the

Answer 1

Like query supports wildcard characters and hence very useful compared to the string extension methods in some scenarios.

For ex: If we were to search all the 4 lettered names with 'ri' as the middle characters we could do EF.Functions.Like(c.Name, "_ri_");

or to get all the customers from cities which start with vowels:

var customers = from c in context.Customers 
                   where EF.Functions.Like(c.City, "[aeiou]%")
                   select c;

(Please read @Tseng's answer on how they are translated differently into SQL queries)

Answer 2

The answer of @adiga is quite incomplete and covers just a part of the differences in usage.

However, .StartsWith(...), .Contains(...) and .EndsWith(...) are also translated differently into SQL then EF.Functions.Like.

For example .StartsWith gets translated as (string LIKE pattern + "%" AND CHARINDEX(pattern, string) = 1) OR pattern = '' where .Contains gets translated into (CHARINDEX(pattern, string) > 0) OR pattern = ''.

EF.Functions.Like however gets translated into string LIKE pattern [ESCAPE escapeChar].

This may also have implications on Performance. The above is valid for EF Core SqlServer provider. Other EF Core providers may translate it differently.