SQL is not a natural place for order and numbering. You can add order with 'order by' but numbering is a bit server-specific. But there are ways. Suppose your text file is in a one column table file_name with a numeric column named idx, and all values are unique. You can select the count of rows where idx < 467456, so you know its nominal 0-based number in an ordered listing. You can now use that number to select from file_name where the count of rows less minus the first subquery is 'between -1 and 1':
Code:
select
b.idx
from file_name b
where ( (
select count(c.*) from file_name c where idx < 467456
) - (
select count(a.*) from file_name a where a.idx < b.idx
) ) between -1 and 1
Hello all,
I have a test file that has the format:
.....
O
3.694950 -.895050 1.480000
O
5.485050 .895050 1.480000
Ti
-4.590000 4.590000 2.960000
Ti
-2.295000 ... (5 Replies)
I have a script problem that I am not able to solve due my very limited understanding of unix/awk.
This is the contents of test.sh
awk '{print $1}'
From the prompt if I enter:
./test.sh Hello World
I would expect to see "Hello" but all I get is a blank line. Only then if I enter "Hello... (2 Replies)
hello folks
i have a file that have data like
/test/aa/123
/test/aa/xyz
/test/bb/xyz
/test/bb/123
in above lines i just wants to grep "aa" and "bb".
Thanks,
Bash (4 Replies)
Hi to all.
I'm trying to sort this with the Unix command sort.
user1:12345678:3.5:2.5:8:1:2:3
user2:12345679:4.5:3.5:8:1:3:2
user3:12345687:5.5:2.5:6:1:3:2
user4:12345670:5.5:2.5:5:3:2:1
user5:12345671:2.5:5.5:7:2:3:1
I need to get this:
user3:12345687:5.5:2.5:6:1:3:2... (7 Replies)
Hi UNIX Gurus,
I want to use extract the where clause of a SQL present in a file. Please suggest me how can I do it.
Select * from emp where emp_id>10;
cat <file_name> | grep -i "where" returns whole SQL.
how can I extract only "where emp_id>10;"
Thanks in advance (4 Replies)
Use and complete the template provided. The entire template must be completed. If you don't, your post may be deleted!
1. The problem statement, all variables and given/known data:
1. Print the number of people that are in the /etc/passwd file with the name of George
2. Sort by name and... (8 Replies)
Hi All,
I want to run multiple sql queries and store the data in variable but i want to use sql command only once. Is there a way without running sql command twice and storing.Please advise.
Eg :
Select 'Query 1 output' from dual;
Select 'Query 2 output' from dual;
I want to... (3 Replies)
Hi, I need to join these statements for efficiency, and without having to make a new directory for each batch. I'm annotating commands below.
wget -q -r -l1 URL
^^ can't use -O - here and pipe | to grep because of -r
grep -hrio "\b\+@\+\.\{2,4\}\+\b" * > first.txt
^^ Need to grep the output... (14 Replies)
Discussion started by: p1ne
14 Replies
LEARN ABOUT DEBIAN
bup-margin
bup-margin(1) General Commands Manual bup-margin(1)NAME
bup-margin - figure out your deduplication safety margin
SYNOPSIS
bup margin [options...]
DESCRIPTION
bup margin iterates through all objects in your bup repository, calculating the largest number of prefix bits shared between any two
entries. This number, n, identifies the longest subset of SHA-1 you could use and still encounter a collision between your object ids.
For example, one system that was tested had a collection of 11 million objects (70 GB), and bup margin returned 45. That means a 46-bit
hash would be sufficient to avoid all collisions among that set of objects; each object in that repository could be uniquely identified by
its first 46 bits.
The number of bits needed seems to increase by about 1 or 2 for every doubling of the number of objects. Since SHA-1 hashes have 160 bits,
that leaves 115 bits of margin. Of course, because SHA-1 hashes are essentially random, it's theoretically possible to use many more bits
with far fewer objects.
If you're paranoid about the possibility of SHA-1 collisions, you can monitor your repository by running bup margin occasionally to see if
you're getting dangerously close to 160 bits.
OPTIONS --predict
Guess the offset into each index file where a particular object will appear, and report the maximum deviation of the correct answer
from the guess. This is potentially useful for tuning an interpolation search algorithm.
--ignore-midx
don't use .midx files, use only .idx files. This is only really useful when used with --predict.
EXAMPLE
$ bup margin
Reading indexes: 100.00% (1612581/1612581), done.
40
40 matching prefix bits
1.94 bits per doubling
120 bits (61.86 doublings) remaining
4.19338e+18 times larger is possible
Everyone on earth could have 625878182 data sets
like yours, all in one repository, and we would
expect 1 object collision.
$ bup margin --predict
PackIdxList: using 1 index.
Reading indexes: 100.00% (1612581/1612581), done.
915 of 1612581 (0.057%)
SEE ALSO bup-midx(1), bup-save(1)BUP
Part of the bup(1) suite.
AUTHORS
Avery Pennarun <apenwarr@gmail.com>.
Bup unknown-bup-margin(1)