Inner join returning all rows.

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Inner join returning all rows.

TryingToLearn

SSCrazy

Points: 2646
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May 3, 2013 at 7:14 am

#277345

I figured it out....Thank you,
I would like to return all the data for a single empnum, but this query is returnng data for ALL empnum's. any suggestion would be greatly appreciated.
select E.empnum, rtrim(C.lname) + ', ' + rtrim(C.fname) as Name,
rtrim(substring(C.dept,1,3)) as Office,
C.dept,
calldate,
duration_in_decimal,
io
from CALLS C INNER JOIN EMP E on C.empnum = E.empnum and C.empnum = 6396 where
(month(calldate) = case month('2012/11/30') when '1' then '12' else month('2012/11/30') - 1 end and
year(calldate) = case month('2012/11/30') when '1' then year('2012/11/30') - 1 else year('2012/11/30') end and duration_in_decimal > .0055555
and (len(phonenum) IN (7,10,11))) or (month(calldate) = case month('2012/11/30') when '1' then '12' else month('2012/11/30') - 1 end and
year(calldate) = case month('2012/11/30') when '1' then year('2012/11/30') - 1 else year('2012/11/30') end and io = 'I')
ORDER BY C.empnum;

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Sean Lange SSC Guru Points: 286590 More actions · Answer 1

TryingToLearn (5/3/2013)
I figured it out....Thank you,
I would like to return all the data for a single empnum, but this query is returnng data for ALL empnum's. any suggestion would be greatly appreciated.
select E.empnum, rtrim(C.lname) + ', ' + rtrim(C.fname) as Name,
rtrim(substring(C.dept,1,3)) as Office,
C.dept,
calldate,
duration_in_decimal,
io
from CALLS C INNER JOIN EMP E on C.empnum = E.empnum and C.empnum = 6396 where
(month(calldate) = case month('2012/11/30') when '1' then '12' else month('2012/11/30') - 1 end and
year(calldate) = case month('2012/11/30') when '1' then year('2012/11/30') - 1 else year('2012/11/30') end and duration_in_decimal > .0055555
and (len(phonenum) IN (7,10,11))) or (month(calldate) = case month('2012/11/30') when '1' then '12' else month('2012/11/30') - 1 end and
year(calldate) = case month('2012/11/30') when '1' then year('2012/11/30') - 1 else year('2012/11/30') end and io = 'I')
ORDER BY C.empnum;

You should move that to the where clause.

So let's look at your where clause a little bit here...

If you have anything resembling a lot of data this is going to crawl like a snail in frozen molasses. You have all sorts of nonSARGable predicates and tons of implicit conversions.

I suspect that what you are doing is creating a big long sql string in your application and then executing it? This code could be greatly improved from a performance standpoint.

Try moving your empnum check to the where clause and see if that helps. Then if you want some help to make this run faster we can take a look.

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Sergiy SSC Guru Points: 110208 More actions · Answer 2

SELECT E.empnum, RTRIM(C.lname) + ', ' + RTRIM(C.fname) AS Name,

RTRIM(SUBSTRING(C.dept,1,3)) AS Office,

C.dept,

calldate,

duration_in_decimal,

io

FROM CALLS C

INNER JOIN ( -- subquery returnig beginning of the curent(?) month. This approach allows us to do the conversion and month calculations just once

SELECT DATEADD(mm, DATEDIFF(mm, 0, CONVERT(DATETIME, '20121130', 112)), 0) MonthStart ) CM

-- selecting the range of dates for calldate - the way allowing to use an index

ON calldate >= DATEADD(mm, -1, MonthStart) AND calldate < MonthStart

INNER JOIN EMP E ON C.empnum = E.empnum

WHERE C.empnum = 6396 -- following Sean's sound advice

AND (

-- now the conditions look pretty straight forward. Please correct it if I made a mistake somewhere.

-- it was not so easy to find the ends in the original version :-)

(duration_in_decimal > .0055555 AND LEN(phonenum) IN (7,10,11))

OR io = 'I'

)

ORDER BY C.empnum;

And one last comment.

I'm pretty sure the table CALLS has a clustered index with 1st column "calldate". Right?

Well, why am I asking? It just cannot be any other way.

Silly me.:hehe:

_____________
Code for TallyGenerator

TryingToLearn SSCrazy Points: 2646 More actions · Answer 3

TryingToLearn

SSCrazy

Points: 2646

May 4, 2013 at 6:38 am

#1612384

Thank you...

TryingToLearn SSCrazy Points: 2646 More actions · Answer 4

TryingToLearn

SSCrazy

Points: 2646

May 4, 2013 at 6:39 am

#1612385

Thank you..

TryingToLearn SSCrazy Points: 2646 More actions · Answer 5

really appreciate your help. This code was written 10 years ago....and i am a little new to coding.

SELECT DATEADD(mm, DATEDIFF(mm, 0, CONVERT(DATETIME, '20121130', 112)), 0) MonthStart ) CM

ON calldate >= DATEADD(mm, -1, MonthStart) AND calldate < MonthStart

Could you pseudo code explain what is happening in this block of code? what i thought it was doing was getting all data for this employee for the month i pass in(20121130). what the CM relates to is confusing me..

Sean Lange SSC Guru Points: 286590 More actions · Answer 6

TryingToLearn (5/7/2013)
really appreciate your help. This code was written 10 years ago....and i am a little new to coding.
SELECT DATEADD(mm, DATEDIFF(mm, 0, CONVERT(DATETIME, '20121130', 112)), 0) MonthStart ) CM
ON calldate >= DATEADD(mm, -1, MonthStart) AND calldate < MonthStart
Could you pseudo code explain what is happening in this block of code? what i thought it was doing was getting all data for this employee for the month i pass in(20121130). what the CM relates to is confusing me..

You are missing the very critical piece of that which is the line above it.

INNER JOIN ( -- subquery returnig beginning of the curent(?) month. This approach allows us to do the conversion and month calculations just once

This is joining to the subselect inside the parenthesis. The CM is the alias for the subselect.

I tried to reformat this a little bit so it might be easier to see what is going on here.

INNER JOIN

( -- subquery returnig beginning of the curent(?) month. This approach allows us to do the conversion and month calculations just once

SELECT DATEADD(mm, DATEDIFF(mm, 0, CONVERT(DATETIME, '20121130', 112)), 0) MonthStart

) CM ON calldate >= DATEADD(mm, -1, MonthStart) AND calldate < MonthStart