diff --git a/src/sql/engine/expr/ob_expr_get_sys_var.cpp b/src/sql/engine/expr/ob_expr_get_sys_var.cpp
index 2e8d7fd662..1b31e62b15 100644
--- a/src/sql/engine/expr/ob_expr_get_sys_var.cpp
+++ b/src/sql/engine/expr/ob_expr_get_sys_var.cpp
@@ -101,7 +101,7 @@ int ObExprGetSysVar::calc_result_type2(ObExprResType &type,
                 OX(type.set_collation_type(conn_coll));
               }
             }
-          } else if (ob_is_int_tc(data_type)) {
+          } else if (ob_is_int_uint_tc(data_type)) {
             type.set_accuracy(ObAccuracy::MAX_ACCURACY2[lib::is_oracle_mode()][data_type]);
           }
         }
diff --git a/src/sql/engine/expr/ob_expr_get_user_var.cpp b/src/sql/engine/expr/ob_expr_get_user_var.cpp
index b5dcfa03ad..a96675cb90 100644
--- a/src/sql/engine/expr/ob_expr_get_user_var.cpp
+++ b/src/sql/engine/expr/ob_expr_get_user_var.cpp
@@ -70,8 +70,7 @@ int ObExprGetUserVar::calc_result_type1(ObExprResType &type,
         }
       }
       if (session_var.meta_.is_decimal_int()) {
-        type.set_precision(wide::ObDecimalIntConstValue::get_max_precision_by_int_bytes(
-          session_var.value_.get_int_bytes()));
+        type.set_precision(static_cast<ObPrecision>(OB_MAX_DECIMAL_POSSIBLE_PRECISION));
       }
       type.set_collation_level(session_var.meta_.get_collation_level());
       type.set_collation_type(session_var.meta_.get_collation_type());
@@ -137,6 +136,11 @@ int ObExprGetUserVar::eval_get_user_var(const ObExpr &expr, ObEvalCtx &ctx, ObDa
           if (is_lob_storage(res_obj.get_type())) {
             OZ(ob_adjust_lob_datum(res_obj, expr.obj_meta_, ctx.exec_ctx_.get_allocator(), res));
           }
+        } else if (sess_obj.is_decimal_int() && sess_obj.get_int_bytes() != sizeof(int512_t)) {
+          ObDecimalIntBuilder res_builder;
+          res_builder.from(sess_obj.get_decimal_int(), sess_obj.get_int_bytes());
+          res_builder.extend(sizeof(int512_t));
+          res.set_decimal_int(res_builder.get_decimal_int(), res_builder.get_int_bytes());
         } else {
           OZ(res.from_obj(sess_obj));
           if (is_lob_storage(sess_obj.get_type())) {
diff --git a/src/sql/engine/expr/ob_expr_oracle_decode.cpp b/src/sql/engine/expr/ob_expr_oracle_decode.cpp
index 1902d54e2a..2590668b4f 100644
--- a/src/sql/engine/expr/ob_expr_oracle_decode.cpp
+++ b/src/sql/engine/expr/ob_expr_oracle_decode.cpp
@@ -154,6 +154,8 @@ int ObExprOracleDecode::calc_result_typeN(ObExprResType &type,
         type.set_calc_type(ObVarcharType);
       } else if (lib::is_oracle_mode() && ob_is_nchar(calc_type.get_type())) {
         type.set_calc_type(ObNVarchar2Type);
+      } else if (ob_is_decimal_int_tc(calc_type.get_type())) {
+        type.set_calc_type(ObNumberType);
       } else {
         // 保留原mysql下的行为
         type.set_calc_type(calc_type.get_type());