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JQuery to check for duplicate ids in a DOM
... to traditional ASP.NET you're a lot more responsible for creating all the ids in your generated page. ASP.NET would give you nasty, but unique ids.
...
Get selected value/text from Select on change
...g JavaScript
<script>
function val() {
d = document.getElementById("select_id").value;
alert(d);
}
</script>
<select onchange="val()" id="select_id">
Using jQuery
$('#select_id').change(function(){
alert($(this).val());
})
...
Insert into a MySQL table or update if exists
...
Use INSERT ... ON DUPLICATE KEY UPDATE
QUERY:
INSERT INTO table (id, name, age) VALUES(1, "A", 19) ON DUPLICATE KEY UPDATE
name="A", age=19
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Difference between id and name attributes in HTML
What is the difference between the id and name attributes? They both seem to serve the same purpose of providing an identifier.
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HTML input - name vs. id [duplicate]
...;input> tag, what is the difference between the use of the name and id attributes especially that I found that they are sometimes named the same?
...
How to use GROUP_CONCAT in a CONCAT in MySQL
...
select id, group_concat(`Name` separator ',') as `ColumnName`
from
(
select
id,
concat(`Name`, ':', group_concat(`Value` separator ',')) as `Name`
from mytbl
group by
id,
`Name`
) tbl
group by id;
You can...
Best way to select random rows PostgreSQL
...pecifications (plus additional info in the comments),
You have a numeric ID column (integer numbers) with only few (or moderately few) gaps.
Obviously no or few write operations.
Your ID column has to be indexed! A primary key serves nicely.
The query below does not need a sequential scan of the...
When should I use cross apply over inner join?
... (
SELECT TOP 3 *
FROM t2
WHERE t2.t1_id = t1.id
ORDER BY
t2.rank DESC
) t2o
It cannot be easily formulated with an INNER JOIN condition.
You could probably do something like that using CTE's and window function:
WITH t2o AS...
Does the join order matter in SQL?
... (commutativity and associativity) properties:
a LEFT JOIN b
ON b.ab_id = a.ab_id
LEFT JOIN c
ON c.ac_id = a.ac_id
is equivalent to:
a LEFT JOIN c
ON c.ac_id = a.ac_id
LEFT JOIN b
ON b.ab_id = a.ab_id
but:
a LEFT JOIN b
ON b.ab_id = a.ab_id
LEFT JOIN c
ON c....
What is the id( ) function used for?
I read the Python 2 docs and noticed the id() function:
13 Answers
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