SqlFuncs add methods

Src/Asp.Net/SqlServerTest/Demo/Demo1_Queryable.cs

@@ -180,6 +180,11 @@ namespace OrmTest
             var test25 = db.Queryable<Order>().Where(it => true).Select(it => new { x1 = it.CreateTime.Month,x2=DateTime.Now.Month}).ToList();
             var test26 = db.Queryable<Order>().Where(it => true).Select(it => new { x1 = it.CreateTime.Day, x2 = DateTime.Now.Day }).ToList();
             var test27 = db.Queryable<Order>().Where(it => true).Select(it => new { x1 = it.CreateTime.Year, x2 = DateTime.Now.Year }).ToList();
+            var test28 = db.Queryable<Order>().Select(it=>SqlFunc.DateDiff(DateType.Day,Convert.ToDateTime("2021-1-1"),Convert.ToDateTime("2021-1-12"))).ToList();
+            var test29 = db.Queryable<Order>().Select(it =>new {x= SqlFunc.LessThan(1, 2) }).ToList();
+            var test30= db.Queryable<Order>().Select(it => new { x = SqlFunc.LessThanOrEqual(1, 2) }).ToList();
+            var test31 = db.Queryable<Order>().Select(it => new { x = SqlFunc.GreaterThan(1, 2) }).ToList();
+            var test32 = db.Queryable<Order>().Select(it => new { x = SqlFunc.GreaterThanOrEqual(1, 2) }).ToList();
             Console.WriteLine("#### Examples End ####");
         }
 

Src/Asp.Net/SqlSugar/ExpressionsToSql/DbMethods/DefaultDbMethod.cs

@@ -490,5 +490,41 @@ namespace SqlSugar
             var parameter2= model.Args[1];
             return string.Format("  ROUND({0},{1}) ", parameter.MemberName, parameter2.MemberName);
         }
+
+        public string DateDiff(MethodCallExpressionModel model) 
+        {
+            var parameter = model.Args[0];
+            var parameter2 = model.Args[1];
+            var parameter3 = model.Args[2];
+            return string.Format(" DATEDIFF({0},{1},{2}) ", parameter.MemberValue?.ToString().ToSqlFilter(), parameter2.MemberName, parameter3.MemberName);
+        }
+        public string GreaterThan(MethodCallExpressionModel model) 
+        {
+            //>
+            var parameter = model.Args[0];
+            var parameter2 = model.Args[1];
+            return string.Format(" ({0} > {1}) ", parameter.MemberName, parameter2.MemberName); 
+        }
+        public string GreaterThanOrEqual(MethodCallExpressionModel model) 
+        {
+            //>=
+            var parameter = model.Args[0];
+            var parameter2 = model.Args[1];
+            return string.Format(" ({0} >= {1}) ", parameter.MemberName, parameter2.MemberName);
+        }
+        public string LessThan(MethodCallExpressionModel model) 
+        {
+            //<
+            var parameter = model.Args[0];
+            var parameter2 = model.Args[1];
+            return string.Format(" ({0} < {1}) ", parameter.MemberName, parameter2.MemberName);
+        }
+        public string LessThanOrEqual(MethodCallExpressionModel model) 
+        {
+            //<=
+            var parameter = model.Args[0];
+            var parameter2 = model.Args[1];
+            return string.Format(" ({0} <= {1}) ", parameter.MemberName, parameter2.MemberName);
+        }
     }
 }

Src/Asp.Net/SqlSugar/ExpressionsToSql/DbMethods/IDbMethods.cs

@@ -75,5 +75,11 @@ namespace SqlSugar
         string Format(MethodCallExpressionModel model);
         string Abs(MethodCallExpressionModel model);
         string Round(MethodCallExpressionModel model);
+
+        string DateDiff(MethodCallExpressionModel model);
+        string GreaterThan(MethodCallExpressionModel model);
+        string GreaterThanOrEqual(MethodCallExpressionModel model);
+        string  LessThan(MethodCallExpressionModel model);
+        string LessThanOrEqual(MethodCallExpressionModel model); 
     }
 }

Src/Asp.Net/SqlSugar/ExpressionsToSql/DbMethods/SqlFunc.cs

@@ -9,6 +9,27 @@ namespace SqlSugar
 {
     public partial class SqlFunc
     {
+
+        public static int DateDiff(DateType dateType,DateTime littleTime, DateTime bigTime) 
+        {
+            throw new NotSupportedException("Can only be used in expressions");
+        }
+        public static bool GreaterThan(object thisValue,object gtValue)
+        {
+            throw new NotSupportedException("Can only be used in expressions");
+        }
+        public static bool GreaterThanOrEqual(object thisValue, object gtValue)
+        {
+            throw new NotSupportedException("Can only be used in expressions");
+        }
+        public static bool LessThan(object thisValue, object ltValue)
+        {
+            throw new NotSupportedException("Can only be used in expressions");
+        }
+        public static bool LessThanOrEqual(object thisValue, object ltValue)
+        {
+            throw new NotSupportedException("Can only be used in expressions");
+        }
         public static bool HasNumber(object thisValue)
         {
             return thisValue.ObjToInt() > 0;

Src/Asp.Net/SqlSugar/ExpressionsToSql/ResolveItems/MethodCallExpressionResolve.cs

@@ -856,6 +856,16 @@ namespace SqlSugar
                         return this.Context.DbMehtods.Abs(model);
                     case "Round":
                         return this.Context.DbMehtods.Round(model);
+                    case "DateDiff":
+                        return this.Context.DbMehtods.DateDiff(model);
+                    case "GreaterThan":
+                        return this.Context.DbMehtods.GreaterThan(model);
+                    case "GreaterThanOrEqual":
+                        return this.Context.DbMehtods.GreaterThanOrEqual(model);
+                    case "LessThan":
+                        return this.Context.DbMehtods.LessThan(model);
+                    case "LessThanOrEqual":
+                        return this.Context.DbMehtods.LessThanOrEqual(model);
                     default:
                         break;
                 }