What SQL Statements are currently running?

Whenever the server is running slow, my initial move is to check what query is running. Using the Activity Monitor shows information about the different connections and the t-sql running. However, in a batch, it will not display what specific sql statement is running within the batch. I found this code snippet that's very helpful to identify the specific SQL Statement that are currently running.

I forgot where I grab this, but I'm very thankful for this code.

SELECT 
[Server] = @@servername
, [Spid] = session_Id
, ecid
, [Database] = DB_NAME(sp.dbid)
, [User] = nt_username
, [Status] = er.status
, [Wait] = wait_type
, [Individual Query] =
  SUBSTRING (qt.text, er.statement_start_offset/2,
  (CASE WHEN er.statement_end_offset = -1
           THEN LEN(CONVERT(NVARCHAR(MAX), qt.text)) * 2
    ELSE er.statement_end_offset END -
   er.statement_start_offset)/2)
,[Parent Query] = qt.text
, Program = program_name
, Hostname
, nt_domain
, start_time
, elapsed_hours = datediff(hh, start_time, getdate())
, elapsed_mins =
  datediff(mi, dateadd(hh,datediff(hh, start_time, getdate()),start_time), getdate())
FROM sys.dm_exec_requests er
INNER JOIN sys.sysprocesses sp ON er.session_id = sp.spid
CROSS APPLY sys.dm_exec_sql_text(er.sql_handle)as qt
WHERE session_Id > 50             
AND session_Id NOT IN (@@SPID)    
ORDER BY 1, 2

I would thank the origin of this code, but I forgot where I got it from... Thank you, nevertheless...


~~ CK

A Sample Table-to-XML conversion.

A question was posted on the forum that I am a member of to convert a table into an XML data. The content of table look like this:

STUDENT_ID   grade
---------- ---------
 abc123     0.2
 abc123     0.4
 abc123     0.7
 def123     0.1
 def123     0.4
 def123     0.5

The request is to convert the above data into:

<Students StudentID="abc123">
  <StudentGrade Grades="0.2" />
  <StudentGrade Grades="0.4" />
  <StudentGrade Grades="0.7" />
</Students>
<Students StudentID="def123">
  <StudentGrade Grades="0.1" />
  <StudentGrade Grades="0.4" />
  <StudentGrade Grades="0.5" />
</Students>

Here's the code I posted as a reply:

declare @TestData Table
(
STUDENT_ID VARCHAR(6),
grade Decimal(2,1)
)

insert into @TestData (student_id, grade)
select 'abc123', 0.2 UNION
select 'abc123', 0.7 UNION
select 'abc123', 0.4 UNION
select 'def123', 0.1 UNION
select 'def123', 0.5 UNION
select 'def123', 0.4

select * from @TestData

;with tag1
as
(
  select distinct student_id
  from @testdata
)
select
  1 as tag,
  0 as parent,
  student_id as [Students!1!StudentID],
  null as [StudentGrade!2!Grades]
from tag1
union all
select
  2 as tag,
  1 as parent,
  t1.student_id as [Students!1!StudentID],
  grade as [StudentGrade!2!Grades]
from tag1 t1
  left join @testdata t2 on t1.student_id = t2.student_id
order by [Students!1!StudentID], [StudentGrade!2!Grades]
for xml explicit

As always, comments are welcome...


~~CK

Returning Sequence of Numbers

For quite sometime, I use COLORDER column of syscolumns table to return a sequential number. I will usually pick a table with large number of columns enough to return my requirement. Until I come across Common Table Expression (CTE). One of the major difference between a CTE and a derived table or sub-query, is that a CTE can be self-referencing or recursive.

Consider returning a series of numbers 1-31.

Here's the code:

WITH Number_Sequence
AS
(
   SELECT 1 AS sequence
   UNION ALL
   SELECT sequence+1
   FROM Number_Sequence W
      WHERE sequence < 31
)
SELECT *
FROM Number_Sequence

Now that it's a result set, it may be used to join to another table. Since this is a CTE and not a physical table, it's not indexed and could degrade processing. Table size should always be considered before joining this CTE to another table.

Here's another sample code that simulate bit positions in a byte:

with GroupNumbers
as
(
   select 1 as byte, 1 as from_bit, 8 as to_bit
   union all
   select byte + 1, from_bit + 8, to_bit + 7
   from GroupNumbers
   where to_bit < 64
)  select * from GroupNumbers

As always, comments are welcome...


~~CK