sql能优化一下么,现在效率好低啦

我随便监控了一个sql,居然嵌套3层无用的表,难过啊!!!

SELECT * FROM ( SELECT * FROM (SELECT DISTINCT * FROM (

    select distinct doc.id DOCID,doc.formid FORMID,fs.flowid FLOWID,pen.flowname FLOWNAME,doc.statelabel STATELABEL,pen.summary SUBJECT,
            doc.AUDITORNAMES,doc.AUDITORLIST,doc.APPLICATIONID,doc.DOMAINID  
    from  OBPM.T_DOCUMENT  doc,OBPM.T_FLOW_INTERVENTION pen,OBPM.T_FLOWSTATERT fs,OBPM.T_NODERT node,OBPM.T_ACTORRT actor  
    where doc.id = pen.id and doc.id =fs.docid and fs.id =node.flowstatert_id and  node.id = actor.nodert_id and doc.issubdoc is null and doc.parent is null
            and doc.state is not null and doc.statelabel is not null  and actor.actorid in ('11e1-af8a-8579dfbb-b7c5-25e754eaf851')
    UNION
    select distinct doc.id DOCID,doc.formid FORMID,fs.flowid FLOWID,rhis.flowname FLOWNAME,doc.statelabel STATELABEL,pen.summary SUBJECT,
            doc.AUDITORNAMES,doc.AUDITORLIST,doc.APPLICATIONID,doc.DOMAINID  
    from  OBPM.T_DOCUMENT  doc,OBPM.T_ACTORHIS ahis,OBPM.T_RELATIONHIS rhis,OBPM.T_FLOW_INTERVENTION pen,OBPM.T_FLOWSTATERT fs
    where doc.id=rhis.docid and rhis.id = ahis.nodehis_id and doc.id = pen.id and doc.id =fs.docid and doc.issubdoc is null and doc.parent is null
            and doc.state is not null and doc.statelabel is not null  and ahis.actorid in ('11e1-af8a-8579dfbb-b7c5-25e754eaf851')

) tab ) table_0 WHERE table_0.DOMAINID ='11e1-ae18-d04ada40-a3b2-4960a74ab202' )

您好，明白您的意思了，关于这部分，晚点会咨询相关的同事，有进展之后再答复您。

您好，sp6这块已经进行优化了，如果您是使用了sp6最新版，如果觉得慢，可以对应在元数据，进行索引优化。

通过联系，客户反馈已经没有其他疑问，同意结贴，感谢反馈