‫کوئری نویسی در EF Core - قسمت هفتم - کار با رشته‌‌ها

var members = context.Members
                                    .Select(member => new { Name = member.Surname + ", " + member.FirstName })
                                    .ToList();

var facilities = context.Facilities
                                        .Where(facility => facility.Name.StartsWith("Tennis"))
                                        .ToList();

var members = context.Members
                                    .Select(member => new { member.MemId, member.Telephone })
                                    .Where(member => member.Telephone.Contains("(")
                                                    && member.Telephone.Contains(")"))
                                    .ToList();

members = context.Members
                                    .Select(member => new { member.MemId, member.Telephone })
                                    .Where(member => EF.Functions.Like(member.Telephone, "%[()]%"))
                                    .ToList();

SELECT   CONVERT (NVARCHAR (MAX), [m].[ZipCode]) AS [Zip]
FROM     [Members] AS [m]
ORDER BY CONVERT (NVARCHAR (MAX), [m].[ZipCode]);

var members = context.Members
                                    .Select(member => new { ZipCode = Convert.ToString(member.ZipCode) })
                                    .OrderBy(m => m.ZipCode)
                                    .ToList();
// Now using LINQ to Objects
members = members.Select(member => new { ZipCode = member.ZipCode.PadLeft(5, '0') })
                                                    .OrderBy(m => m.ZipCode)
                                                    .ToList();

namespace EFCorePgExercises.Utils
{
    public static class SqlDbFunctionsExtensions
    {
        public static string SqlReplicate(string expression, int count)
            => throw new InvalidOperationException($"{nameof(SqlReplicate)} method cannot be called from the client side.");

        private static readonly MethodInfo _sqlReplicateMethodInfo = typeof(SqlDbFunctionsExtensions)
            .GetRuntimeMethod(
                nameof(SqlDbFunctionsExtensions.SqlReplicate),
                new[] { typeof(string), typeof(int) }
            );


        public static void AddCustomSqlFunctions(this ModelBuilder modelBuilder)
        {
            modelBuilder.HasDbFunction(_sqlReplicateMethodInfo)
                .HasTranslation(args =>
                {
                    return SqlFunctionExpression.Create("REPLICATE",
                        args,
                        _sqlReplicateMethodInfo.ReturnType,
                        typeMapping: null);
                });
        }
    }
}

namespace EFCorePgExercises.DataLayer
{
    public class ApplicationDbContext : DbContext
    {
         // ...

        protected override void OnModelCreating(ModelBuilder modelBuilder)
        {
         // ...
            modelBuilder.AddCustomSqlFunctions();
         // ...
        }
    }
}

var newMembers = context.Members
                                        .Select(member => new
                                        {
                                            ZipCode =
                                                SqlDbFunctionsExtensions.SqlReplicate(
                                                    "0", 5 - Convert.ToString(member.ZipCode).Length)
                                                + member.ZipCode
                                        })
                        .OrderBy(m => m.ZipCode)
                        .ToList();

var members = context.Members
                                    .Select(member => new { Letter = member.Surname.Substring(0, 1) })
                                    .GroupBy(m => m.Letter)
                                    .Select(g => new
                                    {
                                        Letter = g.Key,
                                        Count = g.Count()
                                    })
                                    .OrderBy(r => r.Letter)
                                    .ToList();

select memid, regexp_replace(telephone, '[^0-9]', '', 'g') as telephone
from members
order by memid;

var members = context.Members
                                .Select(member => new
                                {
                                    member.MemId,
                                    Telephone = member.Telephone.Replace("-", "")
                                                        .Replace("(", "")
                                                        .Replace(")", "")
                                                        .Replace(" ", "")
                                })
                                .OrderBy(r => r.MemId)
                                .ToList();