大约有 40,000 项符合查询结果（耗时：0.0456秒） [XML]
Fastest way to determine if record exists
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SELECT TOP 1 products.id FROM products WHERE products.id = ?; will outperform all of your suggestions as it will terminate execution after it finds the first record.
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How can I remove or replace SVG content?
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Here is the solution:
d3.select("svg").remove();
This is a remove function provided by D3.js.
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django: BooleanField, how to set the default value to true?
...ou want to dynamically choose at runtime whether or not your field will be selected by default, you can use the initial parameter to the form when you initialize it:
form = MyForm(initial={'my_field':True})
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Expert R users, what's in your .Rprofile? [closed]
...se it might breaks my coauthors' code, I wish it was the default. Why?
1) Character vectors use less memory (but only barely);
2) More importantly, we would avoid problems such as:
> x <- factor(c("a","b","c"))
> x
[1] a b c
Levels: a b c
> x <- c(x, "d")
> x
[1] "1" "2" "3" "...
How to find all combinations of coins when given some dollar value
...n.
#include <stdio.h>
#include <stdlib.h>
int main(int argc, char *argv[])
{
if (argc != 2)
{
printf("usage: change amount-in-cents\n");
return 1;
}
int total = atoi(argv[1]);
printf("quarter\tdime\tnickle\tpenny\tto make %d\n", total);
int co...
jQuery Get Selected Option From Dropdown
Usually I use $("#id").val() to return the value of the selected option, but this time it doesn't work.
The selected tag has the id aioConceptName
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Query to count the number of tables I have in MySQL
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SELECT COUNT(*) FROM information_schema.tables WHERE table_schema = 'dbName';
Source
This is mine:
USE databasename;
SHOW TABLES;
SELECT FOUND_ROWS();
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jQuery removing '-' character from string
I have a string "-123445". Is it possible to remove the '-' character from the string?
3 Answers
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How to select/get drop down option in Selenium 2
...converting my selenium 1 code to selenium 2 and can't find any easy way to select a label in a drop down menu or get the selected value of a drop down. Do you know how to do that in Selenium 2?
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How do I see all foreign keys to a table or column?
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For a Table:
SELECT
TABLE_NAME,COLUMN_NAME,CONSTRAINT_NAME, REFERENCED_TABLE_NAME,REFERENCED_COLUMN_NAME
FROM
INFORMATION_SCHEMA.KEY_COLUMN_USAGE
WHERE
REFERENCED_TABLE_SCHEMA = '<database>' AND
REFERENCED_TABLE_NAME = '<...