Sponsored Content
Top Forums Programming Getting Rows from a MySQL Table with max values? Post 302633833 by Corona688 on Wednesday 2nd of May 2012 01:51:29 PM
Old 05-02-2012
Quote:
Originally Posted by Astrocloud
How do get it to show the max value of the DR_RefKey, w multiple rows?
It has to be something that, theoretically, can be done in a single pass.

It can find the highest value easily enough it needn't print anything until it's over. But to find all rows that match the highest value in one pass, it would need to be psychic -- it has to scan the entire table to figure out what the highest is. Once it's done that it's already printed all the results and can't start over.

Indexes and the like make searching and min/max a lot faster than brute-force table scans now, but they aren't used to make the database 'psychic' this way, because that'd mean inconsistent behavior.
This User Gave Thanks to Corona688 For This Post:
 

10 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

max values amd min values

Hello every one, I have following data ***CAMPAIGN 1998 CONTRIBUTIONS*** --------------------------------------------------------------------------- NAME PHONE Jan | Feb | Mar | Total Donated ... (12 Replies)
Discussion started by: devmiral
12 Replies

2. Shell Programming and Scripting

select values from db1 table and insert into table of DB2

Hi I am having three oracle databases running in three different machine. their ip address is different. from one of the DB am able to access both the databases.(means am able to select values and insert values in to tables individually.) I need to fetch some data from DB1 table(say DB1 ip is... (2 Replies)
Discussion started by: aemunathan
2 Replies

3. Shell Programming and Scripting

Select record with MAX value in MySQL

Hi there, I have trouble selecting record that contain one biggest value for a group of other values. I mean, this is my table: mysql> SELECT * FROM b; +----+------+-------+ | id | user | value | +----+------+-------+ | 1 | 1 | 100 | | 3 | 1 | 150 | | 5 | 1 | 300 | | 6... (20 Replies)
Discussion started by: chebarbudo
20 Replies

4. Shell Programming and Scripting

Compare values in two files. For matching rows print corresponding values from File 1 in File2.

- I have two files (File 1 and File 2) and the contents of the files are mentioned below. - I am trying to compare the values of Column1 of File1 with Column1 of File2. If a match is found, print the corresponding value from Column2 of File1 in Column5 of File2. - I tried to modify and use... (10 Replies)
Discussion started by: Santoshbn
10 Replies

5. UNIX for Dummies Questions & Answers

get max value every 4 rows between 2 column

Hi all I have a file that has two columns and I need the maximum value in column 2 of 4 positions o rows. for example at position {1..3} there are 4 characters (A, C, G and T) each of these characters with a value with a value in column 2. I need the maximum value in column 2 and the corresponding... (2 Replies)
Discussion started by: xinox
2 Replies

6. Shell Programming and Scripting

Query the table and return values to shell script and search result values from another files.

Hi, I need a shell script, which would search the result values from another files. 1)execute " select column1 from table_name" query on the table. 2)Based on the result, need to be grep from .wft files. could please explain about this.Below is the way i am using. #!/bin/sh... (4 Replies)
Discussion started by: Rami Reddy
4 Replies

7. Shell Programming and Scripting

Retrieve multiple rows from mysql and automatically create a table

Hi, i want to create a table automatically based on another table (sms_key). For example; If user create a new row with sms_keyword field: IRC then a table created automatically (with some field on it, like: name, ph_number, messages). select * from sms_key; +-------------+ |... (1 Reply)
Discussion started by: jazzyzha
1 Replies

8. Shell Programming and Scripting

Median and max of duplicate rows

Hi all, plz help me with this, I want to to extract the duplicate rows (column 1) in a file which at least repeat 4 times. then I want to summarize them by getting the max , mean, median and min. The file is sorted by column 1, all the repeated rows appear together. If number of elements is... (5 Replies)
Discussion started by: ritakadm
5 Replies

9. Shell Programming and Scripting

awk file to read values from Db2 table replacing hard coded values

Hi, I want to replace a chain of if-else statement in an old AWK file with values from Db2 table or CSV file. The part of code is below... if (start_new_rec=="true"){ exclude_user="false"; user=toupper($6); match(user, "XXXXX."); if (RSTART ==2 ) { ... (9 Replies)
Discussion started by: asandy1234
9 Replies

10. Programming

Php number array from max, min, step size mysql data

I want to create a form with data values in a dropdown list. The values in the dropdown list need to be generated on the fly from max, min and increment values contained in a mysql database. Hopefully this makes sense, I really have no idea where to start :confused: Thanks (6 Replies)
Discussion started by: barrydocks
6 Replies
RAND(3) 								 1								   RAND(3)

rand - Generate a random integer

SYNOPSIS
int rand (void ) DESCRIPTION
int rand (int $min, int $max) If called without the optional $min, $max arguments rand(3) returns a pseudo-random integer between 0 and getrandmax(3). If you want a random number between 5 and 15 (inclusive), for example, use rand(5, 15). Caution This function does not generate cryptographically secure values, and should not be used for cryptographic purposes. If you need a cryptographically secure value, consider using random_int(3), random_bytes(3), or openssl_random_pseudo_bytes(3) instead. Note On some platforms (such as Windows), getrandmax(3) is only 32767. If you require a range larger than 32767, specifying $min and $max will allow you to create a range larger than this, or consider using mt_rand(3) instead. PARAMETERS
o $min - The lowest value to return (default: 0) o $max - The highest value to return (default: getrandmax(3)) RETURN VALUES
A pseudo random value between $min (or 0) and $max (or getrandmax(3), inclusive). EXAMPLES
Example #1 rand(3) example <?php echo rand() . " "; echo rand() . " "; echo rand(5, 15); ?> The above example will output something similar to: 7771 22264 11 SEE ALSO
srand(3), getrandmax(3), mt_rand(3), random_int(3), random_bytes(3), openssl_random_pseudo_bytes(3). PHP Documentation Group RAND(3)
All times are GMT -4. The time now is 01:13 PM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy