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
Template::Plugin::Table(3pm)				User Contributed Perl Documentation			      Template::Plugin::Table(3pm)

NAME
Template::Plugin::Table - Plugin to present data in a table SYNOPSIS
[% USE table(list, rows=n, cols=n, overlap=n, pad=0) %] [% FOREACH item IN table.row(n) %] [% item %] [% END %] [% FOREACH item IN table.col(n) %] [% item %] [% END %] [% FOREACH row IN table.rows %] [% FOREACH item IN row %] [% item %] [% END %] [% END %] [% FOREACH col IN table.cols %] [% col.first %] - [% col.last %] ([% col.size %] entries) [% END %] DESCRIPTION
The "Table" plugin allows you to format a list of data items into a virtual table. When you create a "Table" plugin via the "USE" directive, simply pass a list reference as the first parameter and then specify a fixed number of rows or columns. [% USE Table(list, rows=5) %] [% USE table(list, cols=5) %] The "Table" plugin name can also be specified in lower case as shown in the second example above. You can also specify an alternative variable name for the plugin as per regular Template Toolkit syntax. [% USE mydata = table(list, rows=5) %] The plugin then presents a table based view on the data set. The data isn't actually reorganised in any way but is available via the "row()", "col()", "rows()" and "cols()" as if formatted into a simple two dimensional table of "n" rows x "n" columns. So if we had a sample "alphabet" list contained the letters '"a"' to '"z"', the above "USE" directives would create plugins that represented the following views of the alphabet. [% USE table(alphabet, ... %] rows=5 cols=5 a f k p u z a g m s y b g l q v b h n t z c h m r w c i o u d i n s x d j p v e j o t y e k q w f l r x We can request a particular row or column using the "row()" and "col()" methods. [% USE table(alphabet, rows=5) %] [% FOREACH item = table.row(0) %] # [% item %] set to each of [ a f k p u z ] in turn [% END %] [% FOREACH item = table.col(2) %] # [% item %] set to each of [ m n o p q r ] in turn [% END %] Data in rows is returned from left to right, columns from top to bottom. The first row/column is 0. By default, rows or columns that contain empty values will be padded with the undefined value to fill it to the same size as all other rows or columns. For example, the last row (row 4) in the first example would contain the values "[ e j o t y undef ]". The Template Toolkit will safely accept these undefined values and print a empty string. You can also use the IF directive to test if the value is set. [% FOREACH item = table.row(4) %] [% IF item %] Item: [% item %] [% END %] [% END %] You can explicitly disable the "pad" option when creating the plugin to returned shortened rows/columns where the data is empty. [% USE table(alphabet, cols=5, pad=0) %] [% FOREACH item = table.col(4) %] # [% item %] set to each of 'y z' [% END %] The "rows()" method returns all rows/columns in the table as a reference to a list of rows (themselves list references). The "row()" methods when called without any arguments calls "rows()" to return all rows in the table. Ditto for "cols()" and "col()". [% USE table(alphabet, cols=5) %] [% FOREACH row = table.rows %] [% FOREACH item = row %] [% item %] [% END %] [% END %] The Template Toolkit provides the "first", "last" and "size" virtual methods that can be called on list references to return the first/last entry or the number of entries in a list. The following example shows how we might use this to provide an alphabetical index split into 3 even parts. [% USE table(alphabet, cols=3, pad=0) %] [% FOREACH group = table.col %] [ [% group.first %] - [% group.last %] ([% group.size %] letters) ] [% END %] This produces the following output: [ a - i (9 letters) ] [ j - r (9 letters) ] [ s - z (8 letters) ] We can also use the general purpose "join" virtual method which joins the items of the list using the connecting string specified. [% USE table(alphabet, cols=5) %] [% FOREACH row = table.rows %] [% row.join(' - ') %] [% END %] Data in the table is ordered downwards rather than across but can easily be transformed on output. For example, to format our data in 5 columns with data ordered across rather than down, we specify "rows=5" to order the data as such: a f . . b g . c h d i e j and then iterate down through each column (a-e, f-j, etc.) printing the data across. a b c d e f g h i j . . . Example code to do so would be much like the following: [% USE table(alphabet, rows=3) %] [% FOREACH cols = table.cols %] [% FOREACH item = cols %] [% item %] [% END %] [% END %] Output: a b c d e f g h i j . . . In addition to a list reference, the "Table" plugin constructor may be passed a reference to a Template::Iterator object or subclass thereof. The Template::Iterator get_all() method is first called on the iterator to return all remaining items. These are then available via the usual Table interface. [% USE DBI(dsn,user,pass) -%] # query() returns an iterator [% results = DBI.query('SELECT * FROM alphabet ORDER BY letter') %] # pass into Table plugin [% USE table(results, rows=8 overlap=1 pad=0) -%] [% FOREACH row = table.cols -%] [% row.first.letter %] - [% row.last.letter %]: [% row.join(', ') %] [% END %] AUTHOR
Andy Wardley <abw@wardley.org> <http://wardley.org/> COPYRIGHT
Copyright (C) 1996-2007 Andy Wardley. All Rights Reserved. This module is free software; you can redistribute it and/or modify it under the same terms as Perl itself. SEE ALSO
Template::Plugin perl v5.14.2 2011-12-20 Template::Plugin::Table(3pm)
All times are GMT -4. The time now is 08:16 PM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy