Update exp to sql

Src/Asp.NetCore2/SqlSeverTest/UserTestCases/UnitTest/UnitManyOtMany2131.cs

@@ -49,8 +49,56 @@ namespace OrmTest
             var list1 = db.Queryable<OperatorInfo>()
                 .Includes(it => it.Roles)
                 .ToList();
+
+            TestLength2(db);
+            TestLength3(db);
+            TestLength1(db);
         }
 
+        private static void TestLength1(SqlSugarClient db)
+        {
+            var par = "aa";
+            db.Queryable<Role>()
+                .Where(it => it.name.ToString().Substring(1, par.Length) == "")
+                .ToList();
+            var sql1 = db.Queryable<Role>()
+               .Where(it => it.name.ToString().Substring(1, par.Length) == "")
+               .ToSqlString();
+
+            if (sql1.Contains("LEN(LEN"))
+            {
+                throw new Exception("error;");
+            }
+        }
+        private static void TestLength2(SqlSugarClient db)
+        {
+            var par = "aa";
+            db.Queryable<Role>()
+                .Where(it => it.name.ToString().Substring(1, "aa".Length) == "")
+                .ToList();
+            var sql1 = db.Queryable<Role>()
+               .Where(it => it.name.ToString().Substring(1, "aa".Length) == "")
+               .ToSqlString();
+
+            if (sql1.Contains("LEN(LEN"))
+            {
+                throw new Exception("error;");
+            }
+        }
+        private static void TestLength3(SqlSugarClient db)
+        { 
+            db.Queryable<Role>()
+                .Where(it => it.name.ToString().Substring(1, it.name.Length) == "")
+                .ToList();
+            var sql1 = db.Queryable<Role>()
+               .Where(it => it.name.ToString().Substring(1, it.name.Length) == "")
+               .ToSqlString();
+
+            if (sql1.Contains("LEN(LEN"))
+            {
+                throw new Exception("error;");
+            }
+        }
         /// <summary>
         /// 描述：
         /// 作者：synjones

Src/Asp.NetCore2/SqlSugar/SqlSugarForCore.nuspec

@@ -2,7 +2,7 @@
 <package >
   <metadata>
     <id>SqlSugarCore</id>
-    <version>5.1.4.145</version>
+    <version>5.1.4.146-preview01</version>
     <authors>sunkaixuan</authors>
     <owners>果糖大数据科技</owners>
     <licenseUrl>http://www.apache.org/licenses/LICENSE-2.0.html</licenseUrl>