Question

我有一个查询要花很长时间。无论如何，有没有更好，更优化的方式编写它：

select 1, my_text from (
    select distinct a.my_text||'_'||b.my_text my_text from (
        select r_id, my_text 
        from tmp_v 
        where r_id in (
            select o_id 
            from tmp_recid
        ) and v_id in (
            select v_id 
            from o_v 
            where v_id in (
                select o_id from tmp_record_vaid 
                union 
                select o_id from tmp_vue_vaid
            ) and va_nm = 'My V'
        )
    ) a,
    (
        select r_id, my_text 
        from tmp_v 
        where r_id in (
            select o_id 
            from tmp_recid
        ) and v_id in (
            select v_id 
            from o_v 
            where v_id in (
                select o_id from tmp_record_vaid 
                union 
                select o_id from tmp_vue_vaid
            ) and va_nm = 'My V 2'
        )
    ) b
where a.r_id = b.r_id
except 
    select e_nm 
    from myp_ent_id 
    where p_m_id = 1 and entity_id in (
        select entity_id 
        from o_e_t 
        where p_m_id = 1 and tag = 'Ample' and tag_category = 'My Type'
    )
) a;

Answer 1

第一级优化：我使用CASE将两个子查询a和b（tmp_v）组合为一个，因为这两个条件都相同。

select 1,my_text(
select distinct string_agg(amytext,'')||'_'||string_agg(bmytext,'') as mytext(
select r_id,case va_nm='My V' then my_text else null end as amy_text,case va_nm='My V 2' then my_text else null end as bmy_text
from tmp_v 
where r_id in 
(select o_id from tmp_recid) 
and v_id in (select v_id from o_v where v_id in (select o_id from tmp_record_vaid union select o_id from tmp_vue_vaid))
)
except 
select e_nm 
from myp_ent_id 
where p_m_id = 1 and entity_id in (
        select entity_id 
        from o_e_t 
        where p_m_id = 1 and tag = 'Ample' and tag_category = 'My Type'
)
)a;

您还可以用EXISTS代替IN。

Answer 2

请尝试以下查询，但“除外查询”除外：

select 1, distinct(CONCAT(TV1.my_text, '_'))
from tmp_v TV1
left outer join tmp_recid TR1 on TR1.o_id = TV1.r_id
left outer join o_v OV1 on OV1.v_id = TV1.v_id and OV1.va_nm in ('My V', 'My V 2')

left outer join tmp_record_vaid TRV1 on OV1.v_id = TRV1.o_id
left outer join tmp_vue_vaid TVV1 on OV1.v_id = TVV1.o_id

where TR1.o_id is not null and (TRV1.o_id is not null OR TVV1.o_id is not null)
group by TV1.r_id

Postgres-查询花费很长时间

2 个答案: