How to execute two commands at the same time in SQL Server 2008

Question

How I can execute two commands at the same time in SQL Server?

I want to get a row count of a table and some row according to the row count. For example I want to get row count of a table and assuming I want to get last 50 rows on a single page.

How can I do this?

EDIT 1):

Consider that I first get count and it return to me 100 and I want to get 80 to 100 recordsin this point another tansaction may delete 70 to 100 records and I can not get appropriate records

Does it have to be in two commands, or are you OK if it is just one? — Brian Webster, Sep 05 '11 at 18:03
If you want to base your selection on the row count - you will need to **first** wait 'til the row count is done - you cannot do this in parallel anyway.... — marc_s, Sep 05 '11 at 19:00

score 2 · Answer 1 · answered Sep 05 '11 at 18:06

Is your requirement to be efficient, or to execute a single command? These do not necessarily result in the same thing. For a good discussion on implementing efficient paging, see this article and this follow-up discussion. Don't re-invent the wheel, and don't assume that a single command that handles both is necessarily going to be more efficient than any other solution.

score 1 · Answer 2 · answered Sep 05 '11 at 18:03

1

select * from tableName1 where column1=(select count(*) from tableName2)

answered Sep 05 '11 at 18:03

x2.

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Iridio · Answer 3 · 2011-09-05T18:14:18.347

1

If I understand correctly you want a query that do the count of all record in the table and at the same time get only 50 row. You can do that with something like this:

Select Top 50 Column1, column2, (Select count(ID) from table1) as total from Table1

Personally I would prefer to execute two queries. One for the count and one for the top 50 rows (much more efficient imo)

edited Sep 05 '11 at 18:14

answered Sep 05 '11 at 18:08

Iridio

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score 1 · Accepted Answer · edited May 23 '17 at 12:04

1

An inline count my be evaluated many times or may give different results. A separate CROSS JOIN approach will give different results at some point

See for why with repro script: can I get count() and rows from one sql query in sql server?

;WITH aCTE AS
(
    SELECT
       *,
       COUNT(*) OVER () AS TotalRows,
       ROW_NUMBER OVER (ORDER BY SomeLatest DESC) AS rn
    FROM
       MyTable
) foo
SELECT
   *
FROM
   foo
WHERE
   rn <= 50

edited May 23 '17 at 12:04

Community

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answered Sep 05 '11 at 19:13

gbn

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sorry @gbn for my confidence is your script return true result always? – Arian Sep 06 '11 at 09:34

How to execute two commands at the same time in SQL Server 2008

4 Answers4