Top Forums Programming MySQL: calculating when query ready Post 303029611 by figaro on Tuesday 29th of January 2019 01:44:49 PM
MySQL: calculating when query ready

I have a big, ugly query which is quadratic in the input size and therefore want to display an approximate completion time prior to sending it off:

Code:
select concat('Ready by ', time(now() + pow(select count(*) as datapoints from data, 2)));

Syntactically this is wrong and is merely illustrative. There is no FROM clause, so I cannot use a traditional subquery. How would this be programmed in MySQL 5.7?
 
Test Your Knowledge in Computers #212
Difficulty: Medium
According to OSPF, an autonomous system boundary router is a router that is connected by using more than one routing protocol and that exchanges routing information with routers autonomous systems.
True or False?

8 More Discussions You Might Find Interesting

1. Programming

How to query one to many mysql

Hi there, I have a hierarchical database that include 4 tables. Table A is the parent of B, B is Parent of C, C is parent of D. If I want to query everything in D that is associated with A.name, how do I do that? Thanks! YanYan (0 Replies)
Discussion started by: pinkgladiator
0 Replies

2. Shell Programming and Scripting

? parameter in mysql query

I am debugging some code and came across ? in the WHERE cause in a mysql query. Is this possible and what situations would this be used? SELECT ip, count FROM table WHERE domain=? thanks & regards (2 Replies)
Discussion started by: hazno
2 Replies

3. Web Development

Complex MySQL Query(s)

Hi all, I have a bit of an issue, I am working on a bit of a CMDB for a friend, it's to do with real estate. Anyway, this is my situation. I have a table which contains all the properties (forsale, sold, etc) in the DB named "property". Now, this is what I want to achieve, I wish to... (5 Replies)
Discussion started by: STOIE
5 Replies

4. Web Development

mysql query help

hello all i have 2 columns every column in the following format column1 2011-04-01 11:39:54 column2 2019-02-03 00:00:00 i want get difference between above data as following 2 days 11:39 how to do so ? i tried many functions but nothing works please advice what is the query... (6 Replies)
Discussion started by: mogabr
6 Replies

5. Shell Programming and Scripting

mysql query in shellscript

Hi, I want to access mysql query from database , for that i have tried the below code #! /bin/bash TABLE_NAME=database1 USER_NAME=root IP_ADDR=111.20.9.256 somevar=`echo "select altid from alert where altid='2724'"| mysql -h $IP_ADDR -u $USER_NAME $TABLE_NAME ` echo $somevar ... (1 Reply)
Discussion started by: aish11
1 Replies

6. Programming

mysql query help

Hello i have created mysql query to compare to values and get difference in percentage as following: SELECT file_name, 100 - ((100 * (SELECT file_count FROM xipi_files z WHERE x.file_group = z.file_group AND x.file_name = z.file_name AND z.insert_date = CURDATE( ) - INTERVAL 1 DAY)) /... (1 Reply)
Discussion started by: mogabr
1 Replies

7. Programming

Need help in mysql query

Hi All, i have a table in mysql with the following data Table name Test Assettype Serial_No Status location Mouse 123456 In Stock chennai Mouse 98765 Allocated chennai Keyboard ... (2 Replies)
Discussion started by: venkitesh
2 Replies

8. Shell Programming and Scripting

Need wrapper around mysql query

Hello Friends, I am using check_mysql_query plugin in nagios to query database and get output. query is working fine but output which i am getting contain query. I want to remove query from output and give custom message which will be simple and understandable. Can you help me here with any... (5 Replies)
Discussion started by: ghpradeep
5 Replies
Devel::Refcount(3pm)					User Contributed Perl Documentation				      Devel::Refcount(3pm)

NAME
"Devel::Refcount" - obtain the REFCNT value of a referent SYNOPSIS
use Devel::Refcount qw( refcount ); my $anon = []; print "Anon ARRAY $anon has " . refcount($anon) . " reference "; my $otherref = $anon; print "Anon ARRAY $anon now has " . refcount($anon) . " references "; DESCRIPTION
This module provides a single function which obtains the reference count of the object being pointed to by the passed reference value. FUNCTIONS
$count = refcount($ref) Returns the reference count of the object being pointed to by $ref. COMPARISON WITH SvREFCNT This function differs from "Devel::Peek::SvREFCNT" in that SvREFCNT() gives the reference count of the SV object itself that it is passed, whereas refcount() gives the count of the object being pointed to. This allows it to give the count of any referent (i.e. ARRAY, HASH, CODE, GLOB and Regexp types) as well. Consider the following example program: use Devel::Peek qw( SvREFCNT ); use Devel::Refcount qw( refcount ); sub printcount { my $name = shift; printf "%30s has SvREFCNT=%d, refcount=%d ", $name, SvREFCNT($_[0]), refcount($_[0]); } my $var = []; printcount 'Initially, $var', $var; my $othervar = $var; printcount 'Before CODE ref, $var', $var; printcount '$othervar', $othervar; my $code = sub { undef $var }; printcount 'After CODE ref, $var', $var; printcount '$othervar', $othervar; This produces the output Initially, $var has SvREFCNT=1, refcount=1 Before CODE ref, $var has SvREFCNT=1, refcount=2 $othervar has SvREFCNT=1, refcount=2 After CODE ref, $var has SvREFCNT=2, refcount=2 $othervar has SvREFCNT=1, refcount=2 Here, we see that SvREFCNT() counts the number of references to the SV object passed in as the scalar value - the $var or $othervar respectively, whereas refcount() counts the number of reference values that point to the referent object - the anonymous ARRAY in this case. Before the CODE reference is constructed, both $var and $othervar have SvREFCNT() of 1, as they exist only in the current lexical pad. The anonymous ARRAY has a refcount() of 2, because both $var and $othervar store a reference to it. After the CODE reference is constructed, the $var variable now has an SvREFCNT() of 2, because it also appears in the lexical pad for the new anonymous CODE block. PURE-PERL FALLBACK An XS implementation of this function is provided, and is used by default. If the XS library cannot be loaded, a fallback implementation in pure perl using the "B" module is used instead. This will behave identically, but is much slower. Rate pp xs pp 225985/s -- -66% xs 669570/s 196% -- SEE ALSO
o Test::Refcount - assert reference counts on objects AUTHOR
Paul Evans <leonerd@leonerd.org.uk> perl v5.14.2 2011-11-15 Devel::Refcount(3pm)

Featured Tech Videos

All times are GMT -4. The time now is 01:29 PM.
Unix & Linux Forums Content Copyright 1993-2020. All Rights Reserved.
Privacy Policy