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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 =...
PHP/MySQL insert row then get 'id'
...);
See mysqli_insert_id().
Whatever you do, don't insert and then do a "SELECT MAX(id) FROM mytable". Like you say, it's a race condition and there's no need. mysqli_insert_id() already has this functionality.
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html select only one checkbox in a group
So how can I only allow a user to select only one checkbox?
16 Answers
16
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SQL Joins Vs SQL Subqueries (Performance)?
...e result i was looking for was 739 elements.
My query at first was this:
SELECT p.id,
p.fixedId,
p.azienda_id,
p.categoria_id,
p.linea,
p.tipo,
p.nome
FROM prodotto p
WHERE p.azienda_id = 2699 AND p.anno = (
SELECT MAX(p2.anno)
FROM prodotto p2
WHERE p2.fixed...
Data structure: insert, remove, contains, get random element, all at O(1)
...o other solutions).
The requirement that's tricky is the "random element" selection: in a hash table, you would need to scan or probe for such an element.
For closed hashing / open addressing, the chance of any given bucket being occupied is size() / capacity(), but crucially this is typically kep...
How do I show an open file in eclipse Package Explorer?
...oices. The choices will vary depending on what plugins you have installed. Select the option you want and press Enter.
The fastest way to select an option is to use the first letter of the option, eg. to go to the Package Explorer, press P (you may have to do this 2 or 3 times depending on how many...
List tables in a PostgreSQL schema
...
You can select the tables from information_schema
SELECT * FROM information_schema.tables
WHERE table_schema = 'public'
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How to find the size of an array in postgresql
...ikely) and are running PostgreSQL 9.4 or higher, you can use cardinality:
SELECT cardinality(id) FROM example;
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Programmatically trigger “select file” dialog box
I have a hidden file input element. Is it possible to trigger its select file dialog box from a button's click event?
13 ...
CSS Selector that applies to elements with two classes
Is there a way to select an element with CSS based on the value of the class attribute being set to two specific classes. For example, let's say I have 3 divs:
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