Update exp to sql

Src/Asp.Net/SqlServerTest/Demos/1_Query.cs

@@ -451,6 +451,7 @@ namespace OrmTest.Demo
             var test49 = db.Queryable<Student>().Where(it => it.CreateTime != null).Where(it => SqlFunc.ToDate(it.CreateTime).Year == DateTime.Now.Year).ToList();
             var test50 = db.Queryable<Student>().Where(it => it.CreateTime != null).Where(it => SqlFunc.ToDate(it.CreateTime).Year == SqlFunc.GetDate().Year).ToList();
             var test51 = db.Queryable<Student>().Select(it=>new { x= SqlFunc.ToDate(it.CreateTime).Year+"-" }).ToList();
+            var test52 = db.Queryable<Student>().Select(it => SqlFunc.IsNull(it.CreateTime, SqlFunc.GetDate())).ToList();
         }
         public static void Page()
         {

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

@@ -422,7 +422,13 @@ namespace SqlSugar
                     methodCallExpressionArgs.IsMember = false;
                 }
             }
-            if (methodCallExpressionArgs.IsMember == false)
+            if (methodCallExpressionArgs.IsMember == false&&(item is MethodCallExpression&&item.ToString()== "GetDate()") || (item is UnaryExpression && ((UnaryExpression)item).Operand.ToString() == "GetDate()")) {
+                var parameterName = this.Context.SqlParameterKeyWord + ExpressionConst.MethodConst + this.Context.ParameterIndex;
+                this.Context.ParameterIndex++;
+                methodCallExpressionArgs.MemberName = value;
+                methodCallExpressionArgs.MemberValue = null;
+            }
+            else if (methodCallExpressionArgs.IsMember == false)
             {
                 var parameterName = this.Context.SqlParameterKeyWord + ExpressionConst.MethodConst + this.Context.ParameterIndex;
                 this.Context.ParameterIndex++;