Sponsored Content
Full Discussion: Optimizing query
Special Forums UNIX and Linux Applications Optimizing query Post 302130033 by matrixmadhan on Friday 3rd of August 2007 12:29:18 AM
Old 08-03-2007
Optimizing query

Hi All,

My first thread to this sub-forum and first thread of this sub-forum Smilie

Here it is,

Am trying to delete duplicates from a table retaining just 1 duplicate value out of the duplicate records

for example : from n records of a table out of which x are duplicates, I want to remove x - 1 records retaining 1 record from the x duplicates

This is the query am using,

but I think this could still be optimized for this query really takes time for huge dumps.

DELETE FROM tableA
WHERE rowid not in
(SELECT MIN(rowid) FROM tableA GROUP BY column1)

Oracle 9i
 

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
DELETE(7)							   SQL Commands 							 DELETE(7)

NAME
DELETE - delete rows of a table SYNOPSIS
DELETE FROM [ ONLY ] table [ WHERE condition ] INPUTS table The name (optionally schema-qualified) of an existing table. condition This is an SQL selection query which returns the rows which are to be deleted. Refer to the SELECT statement for further description of the WHERE clause. OUTPUTS DELETE count Message returned if items are successfully deleted. The count is the number of rows deleted. If count is 0, no rows were deleted. DESCRIPTION
DELETE removes rows which satisfy the WHERE clause from the specified table. If the condition (WHERE clause) is absent, the effect is to delete all rows in the table. The result is a valid, but empty table. Tip: TRUNCATE [truncate(7)] is a PostgreSQL extension which provides a faster mechanism to remove all rows from a table. By default DELETE will delete tuples in the table specified and all its sub-tables. If you wish to only update the specific table men- tioned, you should use the ONLY clause. You must have write access to the table in order to modify it, as well as read access to any table whose values are read in the condition. USAGE
Remove all films but musicals: DELETE FROM films WHERE kind <> 'Musical'; SELECT * FROM films; code | title | did | date_prod | kind | len -------+---------------------------+-----+------------+---------+------- UA501 | West Side Story | 105 | 1961-01-03 | Musical | 02:32 TC901 | The King and I | 109 | 1956-08-11 | Musical | 02:13 WD101 | Bed Knobs and Broomsticks | 111 | | Musical | 01:57 (3 rows) Clear the table films: DELETE FROM films; SELECT * FROM films; code | title | did | date_prod | kind | len ------+-------+-----+-----------+------+----- (0 rows) COMPATIBILITY
SQL92 SQL92 allows a positioned DELETE statement: DELETE FROM table WHERE CURRENT OF cursor where cursor identifies an open cursor. Interactive cursors in PostgreSQL are read-only. SQL - Language Statements 2002-11-22 DELETE(7)
All times are GMT -4. The time now is 09:58 PM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy