Sponsored Content
Full Discussion: Optimizing query
Special Forums UNIX and Linux Applications Optimizing query Post 302130206 by matrixmadhan on Friday 3rd of August 2007 02:16:21 PM
Old 08-03-2007
Quote:
Originally Posted by kahuna
I don't know if this is more efficient, but it seems like a positive approach might be better where there are only a few duplicates.

DELETE FROM tableA A1
WHERE column1 in (SELECT column1 FROM tableA GROUP BY column1 having count(*) > 1)
and rowid != (select min(rowid) from tableA A2 where A1.column1 = A2.column1)

Correct me if am wrong !

Am not able to understand the optimization that you have made to make the query run faster.

Basically, with combination of using selected columns ( column1 ) and the specific rowids ( rowid ), what is the need to specify an extra condition with a separate subquery to extract column1.

Isnt that redundant ? Or how does it make the query optimized and more efficient.

This is really equivalent to for each record with a rowid ' x ', necessarily two subqueries should be executed for all the records.

Last edited by reborg; 08-03-2007 at 03:30 PM..
 

10 More Discussions You Might Find Interesting

1. Filesystems, Disks and Memory

Optimizing the system reliability

My product have around 10-15 programs/services running in the sun box, which together completes a task, sequentially. Several instances of the each program/service are running in the unix box, to manage the load and for risk-management reasons. As of now, we dont follow a strict strategy in... (2 Replies)
Discussion started by: Deepa
2 Replies

2. Filesystems, Disks and Memory

optimizing disk performance

I have some questions regarding disk perfomance, and what I can do to make it just a little (or much :)) more faster. From what I've heard the first partitions will be faster than the later ones because tracks at the outer edges of a hard drive platter simply moves faster. But I've also read in... (4 Replies)
Discussion started by: J.P
4 Replies

3. Shell Programming and Scripting

Optimizing for a Speed-up

How would one go about optimizing this current .sh program so it works at a more minimal time. Such as is there a better way to count what I need than what I have done or better way to match patterns in the file? Thanks, #declare variables to be used. help=-1 count=0 JanCount=0 FebCount=0... (3 Replies)
Discussion started by: switch
3 Replies

4. OS X (Apple)

Optimizing OSX

Hi forum, I'm administrating a workstation/server for my lab and I was wondering how to optimize OSX. I was wondering what unnecessary background tasks I could kick off the system so I free up as much memory and cpu power. Other optimization tips are also welcome (HD parameters, memory... (2 Replies)
Discussion started by: deiphon
2 Replies

5. Shell Programming and Scripting

Optimizing the code

Hi, I have two files in the format listed below. I need to find out all values from field 12 to field 20 present in file 2 and list them in file3(format as file2) File1 : FEIN,CHRISTA... (2 Replies)
Discussion started by: nua7
2 Replies

6. Shell Programming and Scripting

Optimizing awk script

Can this awk statement be optimized? i ask because log.txt is a giant file with several hundred thousands of lines of records. myscript.sh: while read line do searchterm="${1}" datecurr=$(date +%s) file=$(awk 'BEGIN{split(ARGV,var,",");print var}' $line) ... (3 Replies)
Discussion started by: SkySmart
3 Replies

7. Shell Programming and Scripting

Optimizing search using grep

I have a huge log file close to 3GB in size. My task is to generate some reporting based on # of times something is being logged. I need to find the number of time StringA , StringB , StringC is being called separately. What I am doing right now is: grep "StringA" server.log | wc -l... (4 Replies)
Discussion started by: Junaid Subhani
4 Replies

8. Shell Programming and Scripting

Optimizing find with many replacements

Hello, I'm looking for advice on how to optimize this bash script, currently i use the shotgun approach to avoid file io/buffering problems of forks trying to write simultaneously to the same file. i'd like to keep this as a fairly portable bash script rather than writing a C routine. in a... (8 Replies)
Discussion started by: f77hack
8 Replies

9. Shell Programming and Scripting

Optimizing bash loop

now, i have to search for a pattern within a particular time frame which the user will provide in the following format: 19/Jun/2018:07:04,21/Jun/2018:21:30 it is easy to get tempted to attempt this search with a variation of the following awk command: awk... (3 Replies)
Discussion started by: SkySmart
3 Replies

10. Web Development

Optimizing JS and CSS

Yes. Got few suggestions. - How about minifying resources - mod_expires - Service workers setup https://www.unix.com/attachments/web-programming/7709d1550557731-sneak-preview-new-unix-com-usercp-vuejs-demo-screenshot-png (8 Replies)
Discussion started by: Akshay Hegde
8 Replies
FBSQL_AFFECTED_ROWS(3)							 1						    FBSQL_AFFECTED_ROWS(3)

fbsql_affected_rows - Get number of affected rows in previous FrontBase operation

SYNOPSIS
int fbsql_affected_rows ([resource $link_identifier]) DESCRIPTION
fbsql_affected_rows(3) returns the number of rows affected by the last INSERT, UPDATE or DELETE query associated with $link_identifier. Note If you are using transactions, you need to call fbsql_affected_rows(3) after your INSERT, UPDATE, or DELETE query, not after the commit. If the last query was a DELETE query with no WHERE clause, all of the records will have been deleted from the table but this function will return zero. Note When using UPDATE, FrontBase will not update columns where the new value is the same as the old value. This creates the possibility that fbsql_affected_rows(3) may not actually equal the number of rows matched, only the number of rows that were literally affected by the query. PARAMETERS
o $ link_identifier -A FrontBase link identifier returned by fbsql_connect(3) or fbsql_pconnect(3).If optional and not specified, the function will try to find an open link to the FrontBase server and if no such link is found it will try to create one as if fbsql_connect(3) was called with no arguments. RETURN VALUES
If the last query failed, this function will return -1. SEE ALSO
fbsql_num_rows(3). PHP Documentation Group FBSQL_AFFECTED_ROWS(3)
All times are GMT -4. The time now is 04:52 AM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy