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Best way to check for “empty or null value”
... '
Demo
Empty string equals any string of spaces when cast to char(n):
SELECT ''::char(5) = ''::char(5) AS eq1
, ''::char(5) = ' '::char(5) AS eq2
, ''::char(5) = ' '::char(5) AS eq3;
Result:
eq1 | eq2 | eq3
----+-----+----
t | t | t
Test for "null or empty string" w...
MySQL: @variable vs. variable. What's the difference?
...ialize this variable with a SET statement or inside a query:
SET @var = 1
SELECT @var2 := 2
When you develop a stored procedure in MySQL, you can pass the input parameters and declare the local variables:
DELIMITER //
CREATE PROCEDURE prc_test (var INT)
BEGIN
DECLARE var2 INT;
SET var2 =...
Replace whole line containing a string using Sed
...nd I couldn't get it to work
I didn't realize some of my issues are coming from unescaped slashes
So here is the solution I came up with which I think should work for most cases:
function escape_slashes {
sed 's/\//\\\//g'
}
function change_line {
local OLD_LINE_PATTERN=$1; shift
lo...
How to get Visual Studio to open Resolve Conflicts window after a TFS Get
...rom Team Explorer. Goto: Pending Changes, then from the Actions drop down, select Resolve Conflicts.
From there you can click Get All Conflicts.
Normally VS will prompt you to resolve any conflicts as soon as you do one of the following:
Get latest
Check in
Merge
...
Specifying rails version to use when creating a new application
...em railties (["3.1.3"]) with executable rails (Gem::GemNotFoundException) from /home/ninad/.rbenv/versions/1.9.2-p290/bin/rails:19:in <main>'
– Ninad
Dec 25 '11 at 11:04
...
Creating a copy of a database in PostgreSQL [closed]
...
To disconnect all other users from the database, you can use this query:
SELECT pg_terminate_backend(pg_stat_activity.pid) FROM pg_stat_activity
WHERE pg_stat_activity.datname = 'originaldb' AND pid <> pg_backend_pid();
...
Peak memory usage of a linux/unix process
...
From the man page: Most information shown by time is derived from the wait3(2) system call. The numbers are only as good as those returned by wait3(2). On systems that do not have a wait3(2) call that returns status inform...
Push commits to another branch
...not existing and) checkout new branch, where you want to push your commit.
Select the commit from the history, which should get commited & pushed to this branch.
Right click and select Cherry pick commit.
Press Cherry pick button afterwards.
The selected commit get's applied to your checked out ...
Is there a download function in jsFiddle?
...
Crucial step missing. After jsfiddle.net/Ua8Cv/show select the javascript, choose view frame source, then save. Not just page source.
– Eric Bridger
Jan 25 '16 at 19:32
...
Node.js/Express.js App Only Works on Port 3000
...t though. Is there something I need to restart? Express can't be restarted from what I can tell and restarting the Node app happens every time I use node app.js.
– Benjamin Martin
Aug 3 '13 at 1:19
...