query "select..." for global table got incorrect results

[yexiaoli88]

• dble version：5.6.29-dble-9.9.9.9-897c31d-20180927074424
• preconditions ：

create table test_global (id int(11) primary key,R_bit bit(64),R_NAME varchar(50),R_COMMENT varchar(50))
insert into test_global (id,R_bit,R_NAME,R_COMMENT) values (1,b'0001', 'a','test001'),(2,b'0010', 'a string','test002'),(3,b'0011', '1','test001'),(4,b'1010', '1','test001')

• configs：

schema.xml

<table name="test_global" dataNode="dn1,dn2,dn3,dn4" type="global"/>

• steps：
  step1. query in dble:

MySQL [testdb]>  select test_global.id,test_global.R_bit,test_global.R_NAME,test_global.R_COMMENT from test_global where true <=(select HEX(R_bit) not like (select 2) from test_global limit 1);
Empty set (0.29 sec)

MySQL [testdb]> select test_global.id,test_global.R_bit,test_global.R_NAME,test_global.R_COMMENT from test_global where false <(select HEX(R_bit) like (select 1) from test_global limit 1);
Empty set (0.01 sec)

step 2 .query in mysql:

mysql> select test_global.id,test_global.R_bit,test_global.R_NAME,test_global.R_COMMENT from test_global where true <=(select HEX(R_bit) not like (select 2) from test_global limit 1);
+----+----------+----------+-----------+
| id | R_bit    | R_NAME   | R_COMMENT |
+----+----------+----------+-----------+
|  1 |         | a        | test001   |
|  2 |         | a string | test002   |
|  3 |         | 1        | test001   |
|  4 |        
 | 1        | test001   |
+----+----------+----------+-----------+
4 rows in set (0.00 sec)

mysql> select test_global.id,test_global.R_bit,test_global.R_NAME,test_global.R_COMMENT from test_global where false <(select HEX(R_bit) like (select 1) from test_global limit 1);
+----+----------+----------+-----------+
| id | R_bit    | R_NAME   | R_COMMENT |
+----+----------+----------+-----------+
|  1 |         | a        | test001   |
|  2 |         | a string | test002   |
|  3 |         | 1        | test001   |
|  4 |        
 | 1        | test001   |
+----+----------+----------+-----------+
4 rows in set (0.00 sec)

• expect result：
  1. query results from dble should be the same with query results from mydsql

/label ~BUG

[yexiaoli88]

verified on version: 5.6.29-dble-9.9.9.9-edff869-20180928061234