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:
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?
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)
Hi there, I have a table that stores multiple records for many different servers, each of which is timestamped ... I wanted to write a query that would enable me to only output the "latest" record (based on timestamp) for each "unique" server. So for example my main table looks like this
... (3 Replies)
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)
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 $somevar
... (1 Reply)
Hi,
I want to run below query on shellscript but having one problm.
ADV=$( mysql -h "$IP_ADDR" -u "$USER_NAME" "$TABLE_NAME" -BNe" SELECT ADV FROM indata where inid='$INSTRUID' and Date='$latest Date';" )
here Date column contans different below dates
2011-12-01... (0 Replies)
Hi,
I want to run below query on shellscript but having one problm.
ADV=$( mysql -h "$IP_ADDR" -u "$USER_NAME" "$TABLE_NAME" -BNe" SELECT ADV FROM indata where inid='$INSTRUID' and Date='$latest Date';" )
here Date column contans different below dates
2011-12-01... (11 Replies)
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)
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
LEARN ABOUT DEBIAN
devel::refcount
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)