Try this:
SELECT hi_proins0.PROC_INST_ID_ processId, act_re_procdef.NAME_ processName,
IFNULL((SELECT COUNT(*) FROM act_hi_taskinst hi_task1
INNER JOIN act_hi_procinst hi_proins1 ON hi_task1.PROC_INST_ID_ = hi_proins1.PROC_INST_ID_
WHERE hi_proins1.PROC_INST_ID_ = hi_proins0.PROC_INST_ID_ AND
hi_task1.ASSIGNEE_ != hi_proins1.START_USER_ID_ AND hi_task1.ASSIGNEE_ = hi_task0.ASSIGNEE_
GROUP BY hi_task1.ASSIGNEE_
), 0 ) approvalNodeCount,
(
...
) spendTime
FROM act_hi_taskinst hi_task0
LEFT JOIN act_hi_procinst hi_proins0 ON hi_proins0.PROC_INST_ID_ = hi_task0.PROC_INST_ID_
INNER JOIN act_re_procdef ON act_re_procdef.ID_ = hi_proins0.PROC_DEF_ID_
GROUP BY hi_proins0.PROC_INST_ID_