使用NOT IN優化查詢（select ...）

Question

-- tf_wfget_appvr_records 
create function [dbo].[tf_wfget_appvr_records] (@cls_id int, @start_date datetime, @end_date datetime, @approver_id int, @co_id varchar(5)) 
returns @wfapp_approver_status 
table 
(app_recgid bigint, 
    app_status varchar(1), 
    app_status_desc varchar(80) 
) 
as 
begin 
insert into @wfapp_approver_status 
(app_recgid, app_status, app_status_desc) 
select a.recgid, a.status, p.action 
from cm_wfapp a 
    inner join cm_process p on a.proc_id = p.recgid 
where a.co_id = @co_id and a.cls_id = @cls_id 
    and a.apply_date between @start_date and @end_date 
    and a.approver_id = @approver_id 

-- insert others from cm_wftrn 
insert into @wfapp_approver_status 
(app_recgid, app_status, app_status_desc) 
select distinct a.recgid, a.status, p.action 
from cm_wftrn c 
    inner join cm_process p on c.proc_id = p.recgid and p.action is not null 
    inner join cm_wfapp a on a.recgid = c.wfapp_id 
where a.co_id = @co_id and a.cls_id = @cls_id 
    and a.apply_date between @start_date and @end_date 
    and c.wfapp_id not in (select app_recgid from @wfapp_approver_status) 
    and c.appr_id = @approver_id 
return 
end 
GO 

它包含NOT IN約束，該約束需要花費大量時間從數據庫中提取結果。 數據庫很明顯。

如何優化此查詢？ 有沒有辦法用NOT IN（select ...）優化查詢？

請幫忙謝謝。

Answer 1

替換您NOT IN與NOT EXISTS操作是這樣的....

insert into @wfapp_approver_status 
(app_recgid, app_status, app_status_desc) 
select distinct a.recgid, a.status, p.action 
from cm_wftrn c 
    inner join cm_process p on c.proc_id = p.recgid and p.action is not null 
    inner join cm_wfapp a on a.recgid = c.wfapp_id 
where a.co_id = @co_id and a.cls_id = @cls_id 
    and a.apply_date between @start_date and @end_date 
    and c.appr_id = @approver_id 
    and not exists (select 1 
        from @wfapp_approver_status 
        WHERE c.wfapp_id = app_recgid)