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What is the error “Every derived table must have its own alias” in MySQL?
...er), which can the be used to refer to it in the rest of the outer query.
SELECT ID FROM (
SELECT ID, msisdn FROM (
SELECT * FROM TT2
) AS T
) AS T
In your case, of course, the entire query could be replaced with:
SELECT ID FROM TT2
...
How to use Checkbox inside Select Option
The client has given me a design which has a Select Option menu containing a checkbox together with the item name as individual items in the list.
Is there anyway possible to add a checkbox inside a Select Option menu?
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When should I use nil and NULL in Objective-C?
...ke a C pointer) in Objective-C. Like nil , NULL got no value nor address.
char *myChar = NULL;
struct MyStruct *dStruct = NULL;
So if there is a situation, when I need to check my struct (structure type variable) is empty or not then, I will use:
if (dStruct == NULL)
NSLog("The struct is emp...
Why do we need argc while there is always a null at the end of argv?
...
...Which is a shame, in a way. If we had int main(char *argv[], int argc, ...), then some programs could just omit the argc because they do not need it. Opposite (needing argc but not argv) is probably never useful in a real program.
– hyde
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boost多索引容器multi_index_container实战 - C/C++ - 清泛网 - 专注C/C++及内核技术
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typedef std::vector<Person::ptr> Persons;
int main(int argc, char *argv[]) {
if (argc != 2) {
printf("Usage: program count\n");
return 0;
}
PersonContainer container;
IdPersons idPersons;
NamePersons namePersons;
p...
Postgres: INSERT if does not exist already
...onditional INSERT in PostgreSQL:
INSERT INTO example_table
(id, name)
SELECT 1, 'John'
WHERE
NOT EXISTS (
SELECT id FROM example_table WHERE id = 1
);
CAVEAT This approach is not 100% reliable for concurrent write operations, though. There is a very tiny race condition between...
PostgreSQL function for last inserted ID
...e:
INSERT INTO persons (lastname,firstname) VALUES ('Smith', 'John');
SELECT currval('persons_id_seq');
The name of the sequence must be known, it's really arbitrary; in this example we assume that the table persons has an id column created with the SERIAL pseudo-type. To avoid relying on thi...
How to order by with union in SQL?
Is it possible to order when the data is come from many select and union it together? Such as
8 Answers
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Convert string with comma to integer
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If someone is looking to sub out more than a comma I'm a fan of:
"1,200".chars.grep(/\d/).join.to_i
dunno about performance but, it is more flexible than a gsub, ie:
"1-200".chars.grep(/\d/).join.to_i
share
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Change the selected value of a drop-down list with jQuery
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jQuery's documentation states:
[jQuery.val] checks, or selects, all the radio buttons, checkboxes, and select options that match the set of values.
This behavior is in jQuery versions 1.2 and above.
You most likely want this:
$("._statusDDL").val('2');
...