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INNER JOIN vs LEFT JOIN performance in SQL Server
...icient indexes to cover the query.
Consider this example:
CREATE TABLE #Test1
(
ID int NOT NULL PRIMARY KEY,
Name varchar(50) NOT NULL
)
INSERT #Test1 (ID, Name) VALUES (1, 'One')
INSERT #Test1 (ID, Name) VALUES (2, 'Two')
INSERT #Test1 (ID, Name) VALUES (3, 'Three')
INSERT #Test1 (ID, Na...
How to test multiple variables against a value?
...wn (False if 0, True otherwise).
You can shorten that using a containment test against a tuple:
if 1 in (x, y, z):
or better still:
if 1 in {x, y, z}:
using a set to take advantage of the constant-cost membership test (in takes a fixed amount of time whatever the left-hand operand is).
When ...
Using semicolon (;) vs plus (+) with exec in find
... called once per file (or other filesystem object) found:
$ find . -name 'test*' -exec echo {} \;
./test.c
./test.cpp
./test.new
./test.php
./test.py
./test.sh
With a plus, the command echo is called once only. Every file found is passed in as an argument.
$ find . -name 'test*' -exec echo {} \...
Evaluate empty or null JSTL c tags
... JSTL?
You can use the empty keyword in a <c:if> for this:
<c:if test="${empty var1}">
var1 is empty or null.
</c:if>
<c:if test="${not empty var1}">
var1 is NOT empty or null.
</c:if>
Or the <c:choose>:
<c:choose>
<c:when test="${empty var1...
What's the difference between [ and [[ in Bash? [duplicate]
...ked at Conditional Expressions section and it lists the same operators as test (and [ ).
4 Answers
...
Check if a string is html or not
...ter regex to use to check if a string is HTML is:
/^/
For example:
/^/.test('') // true
/^/.test('foo bar baz') //true
/^/.test('<p>fizz buzz</p>') //true
In fact, it's so good, that it'll return true for every string passed to it, which is because every string is HTML. Seriously, ...
Pass request headers in a jQuery AJAX GET call
... type: "GET",
beforeSend: function(xhr){xhr.setRequestHeader('X-Test-Header', 'test-value');},
success: function() { alert('Success!' + authHeader); }
});
http://api.jquery.com/jQuery.ajax/
http://www.w3.org/TR/XMLHttpRequest/#the-setrequestheader-method
...
“#include” a text file in a C program as a char[]
...o the new raw string literals:
In C++ do this:
const char *s =
#include "test.txt"
;
In the text file do this:
R"(Line 1
Line 2
Line 3
Line 4
Line 5
Line 6)"
So there must only be a prefix at the top of the file and a suffix at the end of it. Between it you can do what you want, no special es...
How do you use variables in a simple PostgreSQL script?
... get the last insert id:
DO $$
DECLARE lastid bigint;
BEGIN
INSERT INTO test (name) VALUES ('Test Name')
RETURNING id INTO lastid;
SELECT * FROM test WHERE id = lastid;
END $$;
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imp...
How do you append to an already existing string?
I want append to a string so that every time I loop over it will add say "test" to the string.
7 Answers
...