diff --git a/src/share/object/ob_obj_cast.cpp b/src/share/object/ob_obj_cast.cpp
index 42a6d3432..9947f872e 100644
--- a/src/share/object/ob_obj_cast.cpp
+++ b/src/share/object/ob_obj_cast.cpp
@@ -4422,25 +4422,36 @@ static int bit_datetime(
   int ret = OB_SUCCESS;
   uint64_t bit_value = in.get_bit();
   int64_t value = 0;
-  ObScale scale = in.get_scale();
   ObScale res_scale = -1;
-  const int32_t BUF_LEN = (OB_MAX_BIT_LENGTH + 7) / 8;
-  int64_t pos = 0;
-  char buf[BUF_LEN];
-  MEMSET(buf, 0, BUF_LEN);
   if (OB_UNLIKELY((ObBitTC != in.get_type_class() || ObDateTimeTC != ob_obj_type_class(expect_type)))) {
     ret = OB_ERR_UNEXPECTED;
     LOG_ERROR("invalid input type", K(ret), K(in), K(expect_type));
-  } else if (OB_FAIL(bit_to_char_array(bit_value, scale, buf, BUF_LEN, pos))) {
-    LOG_WARN("fail to store val", KP(buf), K(BUF_LEN), K(bit_value), K(pos));
-  } else {
-    ObString str(pos, buf);
+  } else if (CM_IS_COLUMN_CONVERT(cast_mode)) {
+    // if cast mode is column convert, using bit as int64 to do cast.
     ObTimeConvertCtx cvrt_ctx(params.dtc_params_.tz_info_, ObTimestampType == expect_type);
-    if (CAST_FAIL(ObTimeConverter::str_to_datetime(str, cvrt_ctx, value, &res_scale))) {
-    } else {
-      SET_RES_DATETIME(out);
-      SET_RES_ACCURACY(DEFAULT_PRECISION_FOR_TEMPORAL, res_scale, DEFAULT_LENGTH_FOR_TEMPORAL);
+    if (CAST_FAIL(ObTimeConverter::int_to_datetime(bit_value, 0, cvrt_ctx, value))) {
+      LOG_WARN("int_to_datetime failed", K(ret), K(bit_value));
     }
+  } else {
+    // using bit as char array to do cast.
+    ObScale scale = in.get_scale();
+    const int32_t BUF_LEN = (OB_MAX_BIT_LENGTH + 7) / 8;
+    int64_t pos = 0;
+    char buf[BUF_LEN];
+    MEMSET(buf, 0, BUF_LEN);
+    if (OB_FAIL(bit_to_char_array(bit_value, scale, buf, BUF_LEN, pos))) {
+      LOG_WARN("fail to store val", KP(buf), K(BUF_LEN), K(bit_value), K(pos));
+    } else {
+      ObString str(pos, buf);
+      ObTimeConvertCtx cvrt_ctx(params.dtc_params_.tz_info_, ObTimestampType == expect_type);
+      if (CAST_FAIL(ObTimeConverter::str_to_datetime(str, cvrt_ctx, value, &res_scale))) {
+        LOG_WARN("int_to_datetime failed", K(ret), K(bit_value), K(str));
+      }
+    }
+  }
+  if (OB_SUCC(ret)) {
+    SET_RES_DATETIME(out);
+    SET_RES_ACCURACY(DEFAULT_PRECISION_FOR_TEMPORAL, res_scale, DEFAULT_LENGTH_FOR_TEMPORAL);
   }
   return ret;
 }
@@ -4451,24 +4462,34 @@ static int bit_date(
   int ret = OB_SUCCESS;
   uint64_t bit_value = in.get_bit();
   int32_t value = 0;
-  ObScale scale = in.get_scale();
   ObScale res_scale = -1;
-  const int32_t BUF_LEN = (OB_MAX_BIT_LENGTH + 7) / 8;
-  int64_t pos = 0;
-  char buf[BUF_LEN];
-  MEMSET(buf, 0, BUF_LEN);
   if (OB_UNLIKELY((ObBitTC != in.get_type_class() || ObDateTC != ob_obj_type_class(expect_type)))) {
     ret = OB_ERR_UNEXPECTED;
     LOG_ERROR("invalid input type", K(ret), K(in), K(expect_type));
-  } else if (OB_FAIL(bit_to_char_array(bit_value, scale, buf, BUF_LEN, pos))) {
-    LOG_WARN("fail to store val", KP(buf), K(BUF_LEN), K(bit_value), K(pos));
-  } else {
-    ObString str(pos, buf);
-    if (CAST_FAIL(ObTimeConverter::str_to_date(str, value))) {
-    } else {
-      SET_RES_DATE(out);
-      SET_RES_ACCURACY(DEFAULT_PRECISION_FOR_TEMPORAL, res_scale, DEFAULT_LENGTH_FOR_TEMPORAL);
+  } else if (CM_IS_COLUMN_CONVERT(cast_mode)) {
+    // if cast mode is column convert, using bit as int64 to do cast.
+    if (CAST_FAIL(ObTimeConverter::int_to_date(bit_value, value))) {
+      LOG_WARN("int_to_date failed", K(ret), K(bit_value));
     }
+  } else {
+    // using bit as char array to do cast.
+    ObScale scale = in.get_scale();
+    const int32_t BUF_LEN = (OB_MAX_BIT_LENGTH + 7) / 8;
+    int64_t pos = 0;
+    char buf[BUF_LEN];
+    MEMSET(buf, 0, BUF_LEN);
+    if (OB_FAIL(bit_to_char_array(bit_value, scale, buf, BUF_LEN, pos))) {
+      LOG_WARN("fail to store val", KP(buf), K(BUF_LEN), K(bit_value), K(pos));
+    } else {
+      ObString str(pos, buf);
+      if (CAST_FAIL(ObTimeConverter::str_to_date(str, value))) {
+        LOG_WARN("str_to_date failed", K(ret), K(bit_value), K(str));
+      }
+    }
+  }
+  if (OB_SUCC(ret)) {
+    SET_RES_DATE(out);
+    SET_RES_ACCURACY(DEFAULT_PRECISION_FOR_TEMPORAL, res_scale, DEFAULT_LENGTH_FOR_TEMPORAL);
   }
   return ret;
 }
@@ -4479,24 +4500,34 @@ static int bit_time(
   int ret = OB_SUCCESS;
   uint64_t bit_value = in.get_bit();
   int64_t value = 0;
-  ObScale scale = in.get_scale();
   ObScale res_scale = -1;
-  const int32_t BUF_LEN = (OB_MAX_BIT_LENGTH + 7) / 8;
-  int64_t pos = 0;
-  char buf[BUF_LEN];
-  MEMSET(buf, 0, BUF_LEN);
   if (OB_UNLIKELY((ObBitTC != in.get_type_class() || ObTimeTC != ob_obj_type_class(expect_type)))) {
     ret = OB_ERR_UNEXPECTED;
     LOG_ERROR("invalid input type", K(ret), K(in), K(expect_type));
-  } else if (OB_FAIL(bit_to_char_array(bit_value, scale, buf, BUF_LEN, pos))) {
-    LOG_WARN("fail to store val", KP(buf), K(BUF_LEN), K(bit_value), K(pos));
-  } else {
-    ObString str(pos, buf);
-    if (CAST_FAIL(ObTimeConverter::str_to_time(str, value, &res_scale))) {
-    } else {
-      SET_RES_TIME(out);
-      SET_RES_ACCURACY(DEFAULT_PRECISION_FOR_TEMPORAL, res_scale, DEFAULT_LENGTH_FOR_TEMPORAL);
+  } else if (CM_IS_COLUMN_CONVERT(cast_mode)) {
+    // if cast mode is column convert, using bit as int64 to do cast.
+    if (CAST_FAIL(ObTimeConverter::int_to_time(bit_value, value))) {
+      LOG_WARN("int_to_time failed", K(ret), K(bit_value));
     }
+  } else {
+    // using bit as char array to do cast.
+    ObScale scale = in.get_scale();
+    const int32_t BUF_LEN = (OB_MAX_BIT_LENGTH + 7) / 8;
+    int64_t pos = 0;
+    char buf[BUF_LEN];
+    MEMSET(buf, 0, BUF_LEN);
+    if (OB_FAIL(bit_to_char_array(bit_value, scale, buf, BUF_LEN, pos))) {
+      LOG_WARN("fail to store val", KP(buf), K(BUF_LEN), K(bit_value), K(pos));
+    } else {
+      ObString str(pos, buf);
+      if (CAST_FAIL(ObTimeConverter::str_to_time(str, value, &res_scale))) {
+        LOG_WARN("str_to_date failed", K(ret), K(bit_value), K(str));
+      }
+    }
+  }
+  if (OB_SUCC(ret)) {
+    SET_RES_TIME(out);
+    SET_RES_ACCURACY(DEFAULT_PRECISION_FOR_TEMPORAL, res_scale, DEFAULT_LENGTH_FOR_TEMPORAL);
   }
   return ret;
 }
@@ -4507,24 +4538,15 @@ static int bit_year(
   int ret = OB_SUCCESS;
   uint64_t bit_value = in.get_bit();
   uint8_t value = 0;
-  ObScale scale = in.get_scale();
   ObScale res_scale = -1;
-  const int32_t BUF_LEN = (OB_MAX_BIT_LENGTH + 7) / 8;
-  int64_t pos = 0;
-  char buf[BUF_LEN];
-  MEMSET(buf, 0, BUF_LEN);
   if (OB_UNLIKELY((ObBitTC != in.get_type_class() || ObYearTC != ob_obj_type_class(expect_type)))) {
     ret = OB_ERR_UNEXPECTED;
     LOG_ERROR("invalid input type", K(ret), K(in), K(expect_type));
-  } else if (OB_FAIL(bit_to_char_array(bit_value, scale, buf, BUF_LEN, pos))) {
-    LOG_WARN("fail to store val", KP(buf), K(BUF_LEN), K(bit_value), K(pos));
+  } else if (CAST_FAIL(ObTimeConverter::int_to_year(bit_value, value))) {
+    LOG_WARN("int_to_year faile", K(ret), K(bit_value));
   } else {
-    ObString str(pos, buf);
-    if (CAST_FAIL(ObTimeConverter::str_to_year(str, value))) {
-    } else {
-      SET_RES_YEAR(out);
-      SET_RES_ACCURACY(DEFAULT_PRECISION_FOR_TEMPORAL, res_scale, DEFAULT_LENGTH_FOR_TEMPORAL);
-    }
+    SET_RES_YEAR(out);
+    SET_RES_ACCURACY(DEFAULT_PRECISION_FOR_TEMPORAL, res_scale, DEFAULT_LENGTH_FOR_TEMPORAL);
   }
   return ret;
 }
@@ -4533,24 +4555,45 @@ static int bit_string(
     const ObObjType expect_type, ObObjCastParams& params, const ObObj& in, ObObj& out, const ObCastMode cast_mode)
 {
   int ret = OB_SUCCESS;
-  UNUSED(cast_mode);
-  ObLength res_length = -1;
-  int32_t bytes_length = 0;
-  const int32_t BUF_LEN = (OB_MAX_BIT_LENGTH + 7) / 8;
-  ObScale scale = in.get_scale();
-  int64_t pos = 0;
-  char buf[BUF_LEN];
-  MEMSET(buf, 0, BUF_LEN);
   uint64_t value = in.get_bit();
+  ObLength res_length = -1;
+  char *res_buf;
+  int32_t bytes_length = 0;
   if (OB_UNLIKELY((ObBitTC != in.get_type_class() ||
                    (ObStringTC != ob_obj_type_class(expect_type) && ObTextTC != ob_obj_type_class(expect_type))))) {
     ret = OB_ERR_UNEXPECTED;
     LOG_ERROR("invalid input type", K(ret), K(in), K(expect_type));
+  } else if (CM_IS_COLUMN_CONVERT(cast_mode)) {
+    // if cast mode is column convert, using bit as int64 to do cast.
+    ObFastFormatInt ffi(value);
+    ObString tmp_str;
+    if (OB_FAIL(convert_string_collation(ObString(ffi.length(), ffi.ptr()),
+            ObCharset::get_system_collation(),
+            tmp_str,
+            params.dest_collation_,
+            params))) {
+      LOG_WARN("fail to convert string collation", K(ret));
+    } else {
+      res_buf = tmp_str.ptr();
+      bytes_length = tmp_str.length();
+    }
   } else {
-    if (OB_FAIL(bit_to_char_array(value, scale, buf, BUF_LEN, pos))) {
-      LOG_WARN("fail to store val", KP(buf), K(BUF_LEN), K(value), K(pos));
-    } else if (OB_FAIL(copy_string(params, expect_type, buf, pos, out))) {
-      LOG_WARN("fail to copy string", KP(buf), K(bytes_length), K(value), K(out), K(expect_type));
+    // using bit as char array to do cast.
+    ObScale scale = in.get_scale();
+    const int32_t BUF_LEN = (OB_MAX_BIT_LENGTH + 7) / 8;
+    int64_t pos = 0;
+    char tmp_buf[BUF_LEN];
+    MEMSET(tmp_buf, 0, BUF_LEN);
+    if (OB_FAIL(bit_to_char_array(value, scale, tmp_buf, BUF_LEN, pos))) {
+      LOG_WARN("fail to store val", KP(tmp_buf), K(BUF_LEN), K(value), K(pos));
+    } else {
+      res_buf = tmp_buf;
+      bytes_length = pos;
+    }
+  }
+  if (OB_SUCC(ret)) {
+    if (OB_FAIL(copy_string(params, expect_type, res_buf, bytes_length, out))) {
+      LOG_WARN("fail to copy string", KP(res_buf), K(bytes_length), K(value), K(out), K(expect_type));
     } else {
       res_length = static_cast<ObLength>(out.get_string_len());
       SET_RES_ACCURACY(DEFAULT_PRECISION_FOR_STRING, DEFAULT_SCALE_FOR_STRING, res_length);
diff --git a/src/sql/engine/expr/ob_datum_cast.cpp b/src/sql/engine/expr/ob_datum_cast.cpp
index e4a623943..b1932a45e 100644
--- a/src/sql/engine/expr/ob_datum_cast.cpp
+++ b/src/sql/engine/expr/ob_datum_cast.cpp
@@ -3359,28 +3359,41 @@ CAST_FUNC_NAME(bit, datetime)
   {
     GET_SESSION()
     {
-      const int32_t BUF_LEN = (OB_MAX_BIT_LENGTH + 7) / 8;
-      int64_t pos = 0;
-      char buf[BUF_LEN] = {0};
-      uint64_t in_val = child_res->get_uint();
-      ObLengthSemantics length = expr.args_[0]->datum_meta_.length_semantics_;
-      if (OB_FAIL(bit_to_char_array(in_val, length, buf, BUF_LEN, pos))) {
-        LOG_WARN("fail to store val", K(buf), K(BUF_LEN), K(in_val), K(pos));
-      } else if (OB_ISNULL(session)) {
-        ret = OB_ERR_UNEXPECTED;
-        LOG_WARN("session is NULL", K(ret));
-      } else {
-        int warning = OB_SUCCESS;
-        ObObjType out_type = expr.datum_meta_.type_;
-        ObString str(pos, buf);
-        ObTimeConvertCtx cvrt_ctx(session->get_timezone_info(), ObTimestampType == out_type);
-        ObScale res_scale;
-        int64_t out_val = 0;
-        if (CAST_FAIL(ObTimeConverter::str_to_datetime(str, cvrt_ctx, out_val, &res_scale))) {
-          LOG_WARN("str_to_datetime failed", K(ret));
+      DEF_IN_OUT_VAL(uint64_t, int64_t, 0);
+      if (CM_IS_COLUMN_CONVERT(expr.extra_)) {
+        // if cast mode is column convert, using bit as int64 to do cast.
+        int64_t int64 = 0;
+        if (OB_FAIL(common_uint_int(expr, ObIntType, in_val, ctx, int64))) {
+          LOG_WARN("common_uint_int failed", K(ret));
+        } else if (OB_UNLIKELY(0 > int64)) {
+          ret = OB_INVALID_DATE_FORMAT;
+          LOG_WARN("invalid date", K(ret), K(int64));
         } else {
-          SET_RES_DATETIME(out_val);
+          ObTimeConvertCtx cvrt_ctx(session->get_timezone_info(), ObTimestampType == expr.datum_meta_.type_);
+          if (CAST_FAIL(ObTimeConverter::int_to_datetime(int64, 0, cvrt_ctx, out_val))) {
+            LOG_WARN("int_datetime failed", K(ret), K(int64));
+          }
         }
+      } else {
+        // using bit as char array to do cast.
+        const int32_t BUF_LEN = (OB_MAX_BIT_LENGTH + 7) / 8;
+        int64_t pos = 0;
+        char buf[BUF_LEN] = {0};
+        ObLengthSemantics length = expr.args_[0]->datum_meta_.length_semantics_;
+        if (OB_FAIL(bit_to_char_array(in_val, length, buf, BUF_LEN, pos))) {
+          LOG_WARN("fail to store val", K(buf), K(BUF_LEN), K(in_val), K(pos));
+        } else {
+          ObObjType out_type = expr.datum_meta_.type_;
+          ObString str(pos, buf);
+          ObTimeConvertCtx cvrt_ctx(session->get_timezone_info(), ObTimestampType == out_type);
+          ObScale res_scale;
+          if (CAST_FAIL(ObTimeConverter::str_to_datetime(str, cvrt_ctx, out_val, &res_scale))) {
+            LOG_WARN("str_to_datetime failed", K(ret));
+          }
+        }
+      }
+      if (OB_SUCC(ret)) {
+        SET_RES_DATETIME(out_val);
       }
     }
   }
@@ -3391,20 +3404,32 @@ CAST_FUNC_NAME(bit, date)
 {
   EVAL_ARG()
   {
-    const int32_t BUF_LEN = (OB_MAX_BIT_LENGTH + 7) / 8;
-    int64_t pos = 0;
-    char buf[BUF_LEN] = {0};
     DEF_IN_OUT_VAL(uint64_t, int32_t, 0);
-    ObLengthSemantics length = expr.args_[0]->datum_meta_.length_semantics_;
-    if (OB_FAIL(bit_to_char_array(in_val, length, buf, BUF_LEN, pos))) {
-      LOG_WARN("fail to store val", K(buf), K(BUF_LEN), K(in_val), K(pos));
-    } else {
-      ObString str(pos, buf);
-      if (CAST_FAIL(ObTimeConverter::str_to_date(str, out_val))) {
-        LOG_WARN("str_to_datetime failed", K(ret));
-      } else {
-        SET_RES_DATE(out_val);
+    if (CM_IS_COLUMN_CONVERT(expr.extra_)) {
+      // if cast mode is column convert, using bit as int64 to do cast.
+      int64_t int64 = 0;
+      if (OB_FAIL(common_uint_int(expr, ObIntType, in_val, ctx, int64))) {
+        LOG_WARN("common_uint_int failed", K(ret));
+      } else if (CAST_FAIL(ObTimeConverter::int_to_date(int64, out_val))) {
+        LOG_WARN("int_to_date failed", K(ret), K(int64), K(out_val));
       }
+    } else {
+      // using bit as char array to do cast.
+      const int32_t BUF_LEN = (OB_MAX_BIT_LENGTH + 7) / 8;
+      int64_t pos = 0;
+      char buf[BUF_LEN] = {0};
+      ObLengthSemantics length = expr.args_[0]->datum_meta_.length_semantics_;
+      if (OB_FAIL(bit_to_char_array(in_val, length, buf, BUF_LEN, pos))) {
+        LOG_WARN("fail to store val", K(buf), K(BUF_LEN), K(in_val), K(pos));
+      } else {
+        ObString str(pos, buf);
+        if (CAST_FAIL(ObTimeConverter::str_to_date(str, out_val))) {
+          LOG_WARN("str_to_datetime failed", K(ret));
+        }
+      }
+    }
+    if (OB_SUCC(ret)) {
+      SET_RES_DATE(out_val);
     }
   }
   return ret;
@@ -3414,20 +3439,31 @@ CAST_FUNC_NAME(bit, time)
 {
   EVAL_ARG()
   {
-    const int32_t BUF_LEN = (OB_MAX_BIT_LENGTH + 7) / 8;
-    int64_t pos = 0;
-    char buf[BUF_LEN] = {0};
     DEF_IN_OUT_VAL(uint64_t, int64_t, 0);
-    ObLengthSemantics length = expr.args_[0]->datum_meta_.length_semantics_;
-    if (OB_FAIL(bit_to_char_array(in_val, length, buf, BUF_LEN, pos))) {
-      LOG_WARN("fail to store val", K(buf), K(BUF_LEN), K(in_val), K(pos));
+    if (CM_IS_COLUMN_CONVERT(expr.extra_)) {
+      // if cast mode is column convert, using bit as int64 to do cast.
+      int64_t int64 = 0;
+      if (OB_FAIL(common_uint_int(expr, ObIntType, in_val, ctx, int64))) {
+        LOG_WARN("common_uint_int failed", K(ret), K(in_val));
+      } else if (OB_FAIL(common_int_time(expr, int64, res_datum))) {
+        LOG_WARN("common_int_time failed", K(ret), K(out_val));
+      }
     } else {
-      ObString str(pos, buf);
-      ObScale res_scale;
-      if (CAST_FAIL(ObTimeConverter::str_to_time(str, out_val, &res_scale))) {
-        LOG_WARN("str_to_datetime failed", K(ret));
+      // using bit as char array to do cast.
+      const int32_t BUF_LEN = (OB_MAX_BIT_LENGTH + 7) / 8;
+      int64_t pos = 0;
+      char buf[BUF_LEN] = {0};
+      ObLengthSemantics length = expr.args_[0]->datum_meta_.length_semantics_;
+      if (OB_FAIL(bit_to_char_array(in_val, length, buf, BUF_LEN, pos))) {
+        LOG_WARN("fail to store val", K(buf), K(BUF_LEN), K(in_val), K(pos));
       } else {
-        SET_RES_TIME(out_val);
+        ObString str(pos, buf);
+        ObScale res_scale;
+        if (CAST_FAIL(ObTimeConverter::str_to_time(str, out_val, &res_scale))) {
+          LOG_WARN("str_to_datetime failed", K(ret));
+        } else {
+          SET_RES_TIME(out_val);
+        }
       }
     }
   }
@@ -3438,20 +3474,13 @@ CAST_FUNC_NAME(bit, year)
 {
   EVAL_ARG()
   {
-    DEF_IN_OUT_VAL(uint64_t, uint8_t, 0);
-    const int32_t BUF_LEN = (OB_MAX_BIT_LENGTH + 7) / 8;
-    int64_t pos = 0;
-    char buf[BUF_LEN] = {0};
-    ObLengthSemantics length = expr.args_[0]->datum_meta_.length_semantics_;
-    if (OB_FAIL(bit_to_char_array(in_val, length, buf, BUF_LEN, pos))) {
-      LOG_WARN("fail to store val", K(buf), K(BUF_LEN), K(in_val), K(pos));
-    } else {
-      ObString str(pos, buf);
-      if (CAST_FAIL(ObTimeConverter::str_to_year(str, out_val))) {
-        LOG_WARN("str_to_datetime failed", K(ret));
-      } else {
-        SET_RES_YEAR(out_val);
-      }
+    // same as uint to year
+    uint64_t in_val = child_res->get_uint();
+    int64_t out_val = 0;
+    if (OB_FAIL(common_uint_int(expr, ObIntType, in_val, ctx, out_val))) {
+      LOG_WARN("common_uint_int failed", K(ret), K(in_val));
+    } else if (OB_FAIL(common_int_year(expr, out_val, res_datum))) {
+      LOG_WARN("common_int_year failed", K(ret), K(out_val));
     }
   }
   return ret;
@@ -3461,17 +3490,26 @@ CAST_FUNC_NAME(bit, string)
 {
   EVAL_ARG()
   {
-    const int32_t BUF_LEN = (OB_MAX_BIT_LENGTH + 7) / 8;
-    int64_t pos = 0;
-    char buf[BUF_LEN] = {0};
     uint64_t in_val = child_res->get_uint();
-    ObLengthSemantics length = expr.args_[0]->datum_meta_.length_semantics_;
-    if (OB_FAIL(bit_to_char_array(in_val, length, buf, BUF_LEN, pos))) {
-      LOG_WARN("fail to store val", K(buf), K(BUF_LEN), K(in_val), K(pos));
+    if (CM_IS_COLUMN_CONVERT(expr.extra_)) {
+      // if cast mode is column convert, using bit as int64 to do cast.
+      ObFastFormatInt ffi(in_val);
+      if (OB_FAIL(common_copy_string_zf(expr, ObString(ffi.length(), ffi.ptr()), ctx, res_datum))) {
+        LOG_WARN("common_copy_string_zf failed", K(ret), K(ObString(ffi.length(), ffi.ptr())));
+      }
     } else {
-      ObString str(pos, buf);
-      if (OB_FAIL(common_copy_string(expr, str, ctx, res_datum))) {
-        LOG_WARN("common_copy_string failed", K(ret));
+      // using bit as char array to do cast.
+      const int32_t BUF_LEN = (OB_MAX_BIT_LENGTH + 7) / 8;
+      int64_t pos = 0;
+      char buf[BUF_LEN] = {0};
+      ObLengthSemantics length = expr.args_[0]->datum_meta_.length_semantics_;
+      if (OB_FAIL(bit_to_char_array(in_val, length, buf, BUF_LEN, pos))) {
+        LOG_WARN("fail to store val", K(ret), K(in_val), K(length), K(buf), K(BUF_LEN), K(pos));
+      } else {
+        ObString str(pos, buf);
+        if (OB_FAIL(common_copy_string(expr, str, ctx, res_datum))) {
+          LOG_WARN("common_copy_string failed", K(ret));
+        }
       }
     }
   }
diff --git a/src/sql/engine/expr/ob_expr_operator.cpp b/src/sql/engine/expr/ob_expr_operator.cpp
index 5f97887d9..605cee606 100644
--- a/src/sql/engine/expr/ob_expr_operator.cpp
+++ b/src/sql/engine/expr/ob_expr_operator.cpp
@@ -202,6 +202,14 @@ int OB_INLINE ObExprOperator::cast_operand_type(
     LOG_DEBUG(
         "need cast operand", K(res_type), K(res_type.get_calc_meta().get_scale()), K(res_obj), K(res_obj.get_scale()));
     ObCastMode cast_mode = get_cast_mode();
+    // In PAD expression, we need add COLUMN_CONVERT to cast mode when cast is
+    // from bit to binary and column convert is set in column_conv_ctx_. The COLUMN_CONVERT
+    // cast mode is used in bit_to_string to decide which cast way is appropriate.
+    if (OB_UNLIKELY(T_FUN_PAD == get_type() && ob_is_bit_tc(param_type) &&
+                    ob_is_varbinary_type(calc_type, calc_collation_type) &&
+                    CM_IS_COLUMN_CONVERT(expr_ctx.column_conv_ctx_.cast_mode_))) {
+      cast_mode |= CM_COLUMN_CONVERT;
+    }
 
     if (ob_is_string_or_lob_type(res_type.get_calc_type()) && res_type.is_zerofill()) {
       // For zerofilled string
diff --git a/src/sql/engine/expr/ob_infix_expression.cpp b/src/sql/engine/expr/ob_infix_expression.cpp
index 142390b25..ed3fd9408 100644
--- a/src/sql/engine/expr/ob_infix_expression.cpp
+++ b/src/sql/engine/expr/ob_infix_expression.cpp
@@ -390,7 +390,7 @@ int ObInfixExpression::eval(
       const int64_t idx = item.get_column();
       if (OB_LIKELY(idx >= 0 && OB_LIKELY(idx < row.count_) && OB_LIKELY(NULL != row.cells_))) {
         stack[pos] = row.cells_[idx];
-        if (OB_UNLIKELY(ObBitType == stack[pos].get_type())) {
+        if (OB_UNLIKELY(ObBitType == stack[pos].get_type() && -1 != item.get_accuracy().get_precision())) {
           // use object scale to store bit length
           stack[pos].set_scale(item.get_accuracy().get_precision());
         } else if (OB_UNLIKELY(ob_is_text_tc(stack[pos].get_type()))) {
@@ -401,7 +401,7 @@ int ObInfixExpression::eval(
       } else if (NULL != ctx.row2_ && NULL != ctx.row2_->cells_ && idx >= row.count_ &&
                  idx - row.count_ < ctx.row2_->count_) {
         stack[pos] = ctx.row2_->cells_[idx - row.count_];
-        if (OB_UNLIKELY(ObBitType == stack[pos].get_type())) {
+        if (OB_UNLIKELY(ObBitType == stack[pos].get_type() && -1 != item.get_accuracy().get_precision())) {
           // use object scale to store bit length
           stack[pos].set_scale(item.get_accuracy().get_precision());
         } else if (-1 != item.get_accuracy().get_scale()) {
@@ -435,6 +435,12 @@ int ObInfixExpression::eval(
             item.get_item_type(),
             "type_name",
             get_type_name(item.get_item_type()));
+      } else {
+        // For expression op, we need set scale info after it has been evaluated.
+        if (OB_UNLIKELY(ObBitType == stack[pos].get_type() && -1 != item.get_accuracy().get_precision())) {
+          // use object scale to store bit length
+          stack[pos].set_scale(item.get_accuracy().get_precision());
+        }
       }
     } else {
       ret = OB_ERR_UNEXPECTED;