Add unit test

Src/Asp.NetCore2/PgSqlTest/UnitTest/UCodeFirst.cs

@@ -1,4 +1,5 @@
-using System;
+using SqlSugar;
+using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Text;
@@ -14,6 +15,34 @@ namespace OrmTest
                 Db.DbMaintenance.DropTable("UnitCodeTest1");
             Db.CodeFirst.InitTables<UnitCodeTest1>();
             Db.CodeFirst.InitTables<UnitIndextest>();
+            var db = Db;
+            db.CurrentConnectionConfig.MoreSettings = new ConnMoreSettings()
+            {
+                PgSqlIsAutoToLower = false,
+                PgSqlIsAutoToLowerCodeFirst = false
+            };
+            db.CodeFirst.InitTables<UpperOrder>();
+            var list = db.Queryable<UpperOrder>().LeftJoin<UpperOrder>((X1, Y1) =>
+              X1.Id == Y1.Id)
+                .Where(X1 => X1.Id == 1)
+                .Select(X1 => new {
+                    x1 = X1.Id,
+                    x2 = X1.Name
+                }).ToList();
+        }
+        public class UpperOrder
+        {
+            [SugarColumn(IsPrimaryKey = true, IsIdentity = true)]
+            public int Id { get; set; }
+
+            public string Name { get; set; }
+            public decimal Price { get; set; }
+            [SugarColumn(IsNullable = true)]
+            public DateTime CreateTime { get; set; }
+            [SugarColumn(IsNullable = true)]
+            public int CustomId { get; set; }
+            [SugarColumn(IsIgnore = true)]
+            public List<OrderItem> Items { get; set; }
         }
         [SqlSugar.SugarIndex("UnitIndextestIndex", nameof(UnitIndextest.Table), SqlSugar.OrderByType.Asc)]
         public class UnitIndextest