Code optimization

Src/Asp.Net/SqlSugar/Abstract/FilterProvider/FilterProvider.cs

@@ -14,7 +14,15 @@ namespace SqlSugar
         {
             if (_Filters == null)
                 _Filters = new List<SqlFilterItem>();
-            _Filters.Add(filter);
+            if (this.Context.CurrentConnectionConfig.IsShardSameThread)
+            {
+                if (!_Filters.Select(it => it.FilterValue(this.Context).Sql).Contains(filter.FilterValue(this.Context).Sql))
+                    _Filters.Add(filter);
+            }
+            else
+            {
+                _Filters.Add(filter);
+            }
             return this;
         }