sql查询数据错误，直连两个observer查询竟然结果不一样

同样一个sql 通过2881 连接两个两个server查询结果不一样！！
SELECT * from
(
SELECT DISTINCT
*
FROM
v_v_diag_obj_class2 a
WHERE
diag_obj_id IN (
SELECT
diag_obj_id
FROM
dw_diag_obj b
WHERE
b.school_code = ‘xmshczx’
AND b.school_term_id = ‘2321’
)
) as aa

并且 在同一个observer中执行
SELECT * from
(
SELECT DISTINCT
*
FROM
v_v_diag_obj_class2 a
WHERE
diag_obj_id IN (
SELECT
diag_obj_id
FROM
dw_diag_obj b
WHERE
b.school_code = ‘xmshczx’
AND b.school_term_id = ‘2321’
)
) as aa
where aa.diag_obj_id=‘232108701175’
sql结果有值，但是去掉where条件查询的结果集中没有diag_obj_id=‘232108701175’ 的记录
求助。。。