Databases
StackOverflow2013
Postsdbo
POHow to optimize T-SQL Query?
 

Note that there are some explanatory texts on larger screens.

plurals
  1. POHow to optimize T-SQL Query?
    primarykey
    data
    text
    <p>I am trying to optimize the following query to increase the performance particularly the joins. I would greatly appreciate any suggestions and help. Thanks a lot. I am thinking to use CTE instead of subqueries</p> <p>Query:</p> <pre><code>Select year(dtb.tbDATE) as YearR, `CONVERT(VARCHAR(12),dtb.tbDATE,110) as DateR, (case when dtb.l_grp_no= 7 then COMPANY_B else COMPANY_A end ) as Portfolio, (case when dtb.past_days between 5 and 30 then '5-30' when dtb.past_days between 31 and 60 then'31-60' when dtb.past_days between 61 and 90 then '61-90' when dtb.past_days &gt;= 91 then '91+' when dtb.past_days &lt;5 then 'Current' else 'Dis_po' end) 'Qdel', case when lsc.SStatusC is not null and dtb.tbDATE&gt; ls.eff_date then lsc.SStatusC else 'XX'end as 'LStatus', count(dtb.refaccno) as lcount, sum (dtb.P_bal) as Lbal from sln.[dbo].[table_dtb] as dtb --left outer join sln.dbo.acct_l la on dtb.accrefno = la.accrefno left outer join (select stat_acct_l.* from sln.dbo.stat_acct_l inner join (select refaccno, max(row_id) as MaxRow_id from sln.dbo.stat_acct_l group by refaccno) as maxStatus on stat_acct_l.refaccno = maxStatus.refaccno and stat_acct_l.row_id = maxStatus.MaxRow_id) as ls on ls.refaccno = dtb.refaccno left outer join dw.dbo.AccSt_C lsc on lsc.Stat_C_ID= ls.status_code_no where dtb.l_grp_no in (7,4,8,15)and dtb.tbDATE &gt; '2010-06-31' and dtb.P_bal+dtb.l_C_bal &gt;0 group by year(dtb.tbDATE), CONVERT(VARCHAR(12),dtb.tbDATE,110), case when dtb.past_days between 5 and 30 then '5-30' when dtb.past_days between 31 and 60 then'31-60' when dtb.past_days between 61 and 90 then '61-90' when dtb.past_days &gt;= 91 then '91+' when dtb.past_days &lt;5 then 'Current' else 'Dis_po' end case when dtb.l_grp_no= 7 then COMPANY_B else COMPANY_A end, case when lsc.SStatusC is not null and dtb.tbDATE&gt; ls.eff_date Yearthen lsc.SStatusC else 'XX' end order by year(dtb.tbDATE), CONVERT(VARCHAR(12),dtb.tbDATE,110), case when dtb.l_grp_no= 7 then COMPANY_Belse COMPANY_A end </code></pre>
    singulars
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PTQuestion
    1. USmarc_s
    1. USposhak
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PO
      singulars
      1. PTAnswer
    2. PO
      singulars
      1. PTAnswer
    3. PO
      singulars
      1. PTAnswer
    1. VO
      singulars
      1. POHow to optimize T-SQL Query?
      1. This table or related slice is empty.
      1. VTApproveEditSuggestion
    1. COThat's a lot of code to wade through. About using cte instead of subqueries though, they are effectively the same thing. The only time cte will give you a performance advantage is if you are using the same subquery twice.
      singulars
      1. POHow to optimize T-SQL Query?
      1. USDan Bracuk
    2. COSQL Server does not cache the results of CTEs, it will reevaluate them each time they are used.
      singulars
      1. POHow to optimize T-SQL Query?
      1. USDavid Knight
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload