using Microsoft.EntityFrameworkCore.Query;

using Microsoft.EntityFrameworkCore.Query.Internal;

using Microsoft.EntityFrameworkCore.Storage;

using System.Linq;

using System.Reflection;

namespace Common.Standard.EFCore

{

    public static class QueryableExtensions

    {

        private static readonly TypeInfo QueryCompilerTypeInfo = typeof(QueryCompiler).GetTypeInfo();

        private static readonly FieldInfo QueryCompilerField = typeof(EntityQueryProvider).GetTypeInfo().DeclaredFields.First(x => x.Name == "_queryCompiler");

        private static readonly FieldInfo QueryModelGeneratorField = typeof(QueryCompiler).GetTypeInfo().DeclaredFields.First(x => x.Name == "_queryModelGenerator");

        private static readonly FieldInfo DataBaseField = QueryCompilerTypeInfo.DeclaredFields.Single(x => x.Name == "_database");

        private static readonly PropertyInfo DatabaseDependenciesField = typeof(Database).GetTypeInfo().DeclaredProperties.Single(x => x.Name == "Dependencies");

        /// <summary>

        /// 获取本次查询SQL语句

        /// </summary>

        /// <typeparam name="TEntity"></typeparam>

        /// <param name="query"></param>

        /// <returns></returns>

        public static string ToSql<TEntity>(this IQueryable<TEntity> query)

        {

            var queryCompiler = (QueryCompiler)QueryCompilerField.GetValue(query.Provider);

            var queryModelGenerator = (QueryModelGenerator)QueryModelGeneratorField.GetValue(queryCompiler);

            var queryModel = queryModelGenerator.ParseQuery(query.Expression);

            var database = DataBaseField.GetValue(queryCompiler);

            var databaseDependencies = (DatabaseDependencies)DatabaseDependenciesField.GetValue(database);

            var queryCompilationContext = databaseDependencies.QueryCompilationContextFactory.Create(false);

            var modelVisitor = (RelationalQueryModelVisitor)queryCompilationContext.CreateQueryModelVisitor();

            modelVisitor.CreateQueryExecutor<TEntity>(queryModel);

            var sql = modelVisitor.Queries.First().ToString();

            return sql;

        }

    }

}

var ss = _context.UserTable.Where(m => m.UserName == "admin");

string sql = ss.ToSql();

public partial class MyDbnContext : DbContext

{

        [Obsolete]

        public static readonly LoggerFactory LoggerFactory = new LoggerFactory(new[] { new DebugLoggerProvider((_, __) => true) });

... ...

        protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)

        {

            base.OnConfiguring(optionsBuilder);

            optionsBuilder.UseLoggerFactory(LoggerFactory);

        }

... ...

}