請高手解決... sql 優化問題。 ? SELECT formResourceName,t.id, p.workflow_name workflowName,p.workflow_type workflowType,p.process_definition_id processDefinitionId ,i.process_instance_id processInstanceId,i.create_time processInstanceCreateTime,i.orderId,i.author,i.author_name authorName,i.flag processInstanceFlag ,t.task_id taskId,t.handle_time handleTime, (case when handle_result='0' then '不通過' when handle_result='1' then '通過' when handle_result='2' then '創建' when handle_result='3' then '撤回' else '通過' end) as handleResult, handle_comments handleComment ,t.handler ,t.handler_name handlerName from workflow_trans t left join workflow_instance i on t.process_instance_id=i.process_instance_id left join workflow_template p on i.process_definition_id=p.process_definition_id WHERE i.status<>'DELETE' AND t.id IN (SELECT max(id) FROM workflow_trans GROUP BY process_instance_id,formResourceName) -- 這里排除重復數據 ? 用id in? 數據很慢。 如何優化？