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How do write IF ELSE statement in a MySQL query
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150
You probably want to use a CASE expression.
They look like this:
SELECT col1, col2, (case wh...
MySQL: @variable vs. variable. What's the difference?
...nitialize 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 var...
Linux command to list all available commands and aliases
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You can use the bash(1) built-in compgen
compgen -c will list all the commands you could run.
compgen -a will list all the aliases you could run.
compgen -b will list all the built-ins you could run.
compgen -k will list all the keywords you co...
jQuery Mobile: document ready vs. page events
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jQuery Mobile 1.4 Update:
My original article was intended for old way of page handling, basically everything before jQuery Mobile 1.4. Old way of handling is now deprecated and it will stay active until (including) jQuery Mobile 1.5, so ...
How do you know when to use fold-left and when to use fold-right?
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105
You can transfer a fold into an infix operator notation (writing in between):
This example fo...
How can I transform between the two styles of public key format, one “BEGIN RSA PUBLIC KEY”, the oth
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11
Using phpseclib, a pure PHP RSA implementation...
<?php
include('Crypt/RSA.php');
$rsa = n...
Reusable library to get human readable version of file size?
... unit in ['','Ki','Mi','Gi','Ti','Pi','Ei','Zi']:
if abs(num) < 1024.0:
return "%3.1f%s%s" % (num, unit, suffix)
num /= 1024.0
return "%.1f%s%s" % (num, 'Yi', suffix)
Supports:
all currently known binary prefixes
negative and positive numbers
numbers larger tha...
What is the significance of 1/1/1753 in SQL Server?
Why 1753? What do they have against 1752? My great great great great great great great grandfather would be very offended.
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Add unique constraint to combination of two columns
...TER TABLE dbo.yourtablename
ADD CONSTRAINT uq_yourtablename UNIQUE(column1, column2);
or
CREATE UNIQUE INDEX uq_yourtablename
ON dbo.yourtablename(column1, column2);
Of course, it can often be better to check for this violation first, before just letting SQL Server try to insert the row and...