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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 =...
SQL Server Script to create a new user
...s using the Login you just declared:
Use YourDatabase;
GO
IF NOT EXISTS (SELECT * FROM sys.database_principals WHERE name = N'NewAdminName')
BEGIN
CREATE USER [NewAdminName] FOR LOGIN [NewAdminName]
EXEC sp_addrolemember N'db_owner', N'NewAdminName'
END;
GO
Now, Logins are a bit more flu...
How do I convert a column of text URLs into active hyperlinks in Excel?
...y name itself HyperAdd.
Sub HyperAdd()
'Converts each text hyperlink selected into a working hyperlink
For Each xCell In Selection
ActiveSheet.Hyperlinks.Add Anchor:=xCell, Address:=xCell.Formula
Next xCell
End Sub
When you're finished pasting your macro, click Close and Re...
What is the difference between Views and Materialized Views in Oracle?
... you. The downside of a view is that its performance depends on how good a select statement the view is based on. If the select statement used by the view joins many tables, or uses joins based on non-indexed columns, the view could perform poorly.
Materialized views
They are similar to regular vi...
querySelector and querySelectorAll vs getElementsByClassName and getElementById in JavaScript
I would like to know what exactly is the difference between querySelector and querySelectorAll against getElementsByClassName and getElementById ?
...
Thread pooling in C++11
...or <ctpl_stl.h> if ou do not have Boost library
int main (int argc, char *argv[]) {
ctpl::thread_pool p(2 /* two threads in the pool */);
int arr[4] = {0};
std::vector<std::future<void>> results(4);
for (int i = 0; i < 8; ++i) { // for 8 iterations,
for ...
Solving “Who owns the Zebra” programmatically?
...
In Prolog, we can instantiate the domain just by selecting elements from it :) (making mutually-exclusive choices, for efficiency). Using SWI-Prolog,
select([A|As],S):- select(A,S,S1),select(As,S1).
select([],_).
left_of(A,B,C):- append(_,[A,B|_],C).
next_to(A,B,C):- l...
Code snippet or shortcut to create a constructor in Visual Studio
...a C# project.
So how to make a constructor
Press Ctrl+K and then Ctrl+X
Select Visual C#
Select ctor
Press Tab
Update: You can also right-click in your code where you want the snippet, and select Insert Snippet from the right-click menu
...
How to get the max of two values in MySQL?
...
Use GREATEST()
E.g.:
SELECT GREATEST(2,1);
Note: Whenever if any single value contains null at that time this function always returns null (Thanks to user @sanghavi7)
s...
Delete with Join in MySQL
...
Since you are selecting multiple tables, The table to delete from is no longer unambiguous. You need to select:
DELETE posts FROM posts
INNER JOIN projects ON projects.project_id = posts.project_id
WHERE projects.client_id = :client_id
...