1.ExpressionContextCase增加Num属性，用于传递跳过的数据数量。

2.OcaenBaseForOracle 重写 GetLimit，使其支持子查询。
3.TDSQLForPGODBC 重写 GetLimit，使其支持子查询。
4.getMyInt和getMyIntNull，获取数据方式改成GetDecimal，只有OcaenBaseForOracle 使用这两个方法，这是为了支持OcaenBaseForOracle 驱动2.0.9以上，请更新驱动到2.0.9以上

Src/Asp.NetCore2/SqlSugar.OceanBaseForOracle/OceanBase/SqlBuilder/OceanBaseForOracleExpressionContext.cs

@@ -72,6 +72,16 @@ namespace SqlSugar.OceanBaseForOracle
                 }
             }
         }
+
+        public override string GetLimit()
+        {
+            int num = 1;
+            if (this.Case?.Num != 1)
+            {
+                num = this.Case.Num;
+            }
+            return (this.Case?.HasWhere == true ? "AND" : "WHERE") + " ROWNUM=" + num;
+        }
     }
     public partial class OceanBaseForOracleMethod : DefaultDbMethod, IDbMethods
     {

Src/Asp.NetCore2/SqlSugar.TDSQLForPGODBC/TDSQLForPG/SqlBuilder/TDSQLForPGODBCExpressionContext.cs

@@ -130,6 +130,16 @@ namespace SqlSugar.TDSQLForPGODBC
                 });
             }
         }
+
+        public override string GetLimit()
+        {
+            int num = 1;
+            if (this.Case.Num != 1)
+            {
+                num = this.Case.Num;
+            }
+            return "limit " + num;
+        }
     }
     public class TDSQLForPGODBCMethod : DefaultDbMethod, IDbMethods
     {

Src/Asp.NetCore2/SqlSugar/Abstract/DbBindProvider/IDataRecordExtensions.cs

@@ -151,7 +151,7 @@ namespace SqlSugar
             }
             if (dr.GetDataTypeName(i) == "NUMBER") 
             {
-               return Convert.ToInt32(dr.GetDouble(i));
+               return Convert.ToInt32(dr.GetDecimal(i));
             }
             var result = dr.GetInt32(i);
             return result;
@@ -160,7 +160,7 @@ namespace SqlSugar
         { 
             if (dr.GetDataTypeName(i) == "NUMBER")
             {
-                return Convert.ToInt32(dr.GetDouble(i));
+                return Convert.ToInt32(dr.GetDecimal(i));
             } 
             var result = dr.GetInt32(i);
             return result;

Src/Asp.NetCore2/SqlSugar/ExpressionsToSql/Common/ExpressionContextCase.cs

@@ -4,11 +4,12 @@ using System.Linq;
 using System.Text;
 using System.Threading.Tasks;
 
-namespace SqlSugar 
+namespace SqlSugar
 {
     public class ExpressionContextCase
     {
         public bool IsDateString { get; set; }
         public bool HasWhere { get; set; }
+        public int Num { get; set; } = 1;
     }
 }

Src/Asp.NetCore2/SqlSugar/ExpressionsToSql/Subquery/Items/SubTake.cs

@@ -86,6 +86,10 @@ namespace SqlSugar
                 {
                     this.Context.Case.HasWhere = this.HasWhere;
                 }
+                if (this?.Context?.Case?.Num != 1)
+                {
+                    this.Context.Case.Num = num;
+                }
                 return this.Context.GetLimit();
             }
             else

Src/Asp.NetCore2/SqlSugar/ExpressionsToSql/Subquery/Items/SubTop.cs

@@ -67,6 +67,10 @@ namespace SqlSugar
             }
             else if (this.Context.GetLimit()!=null)
             {
+                if (this?.Context?.Case?.HasWhere == true)
+                {
+                    this.Context.Case.HasWhere = this.HasWhere;
+                }
                 return this.Context.GetLimit();
             }
             else