diff --git a/src/sql/engine/expr/ob_expr_sign.cpp b/src/sql/engine/expr/ob_expr_sign.cpp
index d7e353495c..f2a73c4d24 100644
--- a/src/sql/engine/expr/ob_expr_sign.cpp
+++ b/src/sql/engine/expr/ob_expr_sign.cpp
@@ -134,6 +134,10 @@ int calc_sign_expr(const ObExpr &expr, ObEvalCtx &ctx, ObDatum &res_datum)
         }
         break;
       }
+      case ObBitTC: {
+        res_int = arg_datum->get_bit() == 0 ? 0 : 1;
+        break;
+      }
       default: {
         ret = OB_ERR_UNEXPECTED;
         LOG_WARN("unexpected arg_type", K(ret), K(arg_type));
diff --git a/tools/deploy/mysql_test/test_suite/static_engine/r/mysql/expr_sign.result b/tools/deploy/mysql_test/test_suite/static_engine/r/mysql/expr_sign.result
index 3b9d5441ec..4e9f589a73 100644
--- a/tools/deploy/mysql_test/test_suite/static_engine/r/mysql/expr_sign.result
+++ b/tools/deploy/mysql_test/test_suite/static_engine/r/mysql/expr_sign.result
@@ -896,3 +896,17 @@ select sign(1E-400) from dual;
 +--------------+
 |            0 |
 +--------------+
+
+##bug:
+drop table if exists t1;
+create table t1(c1 bit(64),c2 bit(64));
+insert into t1(c1) values(1);
+
+select sign(c1) from t1;
++----------+
+| sign(c1) |
++----------+
+|        1 |
++----------+
+
+drop table t1;
diff --git a/tools/deploy/mysql_test/test_suite/static_engine/t/expr_sign.test b/tools/deploy/mysql_test/test_suite/static_engine/t/expr_sign.test
index 2aa68ed2c4..cbaab9a27d 100644
--- a/tools/deploy/mysql_test/test_suite/static_engine/t/expr_sign.test
+++ b/tools/deploy/mysql_test/test_suite/static_engine/t/expr_sign.test
@@ -147,3 +147,16 @@ select sign( cast(a2 as char(1024)) ) , sign( cast(a4 as char(1024)) ) from t2 f
 --echo #
 select sign(1E-300) from dual;
 select sign(1E-400) from dual;
+
+##bug:
+
+--disable_warnings
+drop table if exists t1;
+--enable_warnings
+
+create table t1(c1 bit(64),c2 bit(64));
+insert into t1(c1) values(1);
+
+select sign(c1) from t1;
+
+drop table t1;