大约有 40,000 项符合查询结果（耗时：0.0313秒） [XML]
MySQL: Fastest way to count number of rows
...s.
The solution is SQL_CALC_FOUND_ROWS. This is usually used when you are selecting rows but still need to know the total row count (for example, for paging).
When you select data rows, just append the SQL_CALC_FOUND_ROWS keyword after SELECT:
SELECT SQL_CALC_FOUND_ROWS [needed fields or *] FROM t...
Adding options to select with javascript
I want this javascript to create options from 12 to 100 in a select with id="mainSelect", because I do not want to create all of the option tags manually. Can you give me some pointers? Thanks
...
Java: Clear the console
...
System.out.println(new String(new char[50]).replace("\0", "\r\n")); will do the job faster and better.
– Aaron Esau
Dec 30 '17 at 0:28
1
...
Set the selected index of a Dropdown using jQuery
...
First of all - that selector is pretty slow. It will scan every DOM element looking for the ids. It will be less of a performance hit if you can assign a class to the element.
$(".myselect")
To answer your question though, there are a few w...
Copying text outside of Vim with set mouse=a enabled
...
Press shift while selecting with the mouse. This will make mouse selection behave as if mouse=a was not enabled.
Note: this trick also applies to "middle button paste": if you want to paste in vim text that was selected outside, press shift w...
How do I (or can I) SELECT DISTINCT on multiple columns?
...
SELECT DISTINCT a,b,c FROM t
is roughly equivalent to:
SELECT a,b,c FROM t GROUP BY a,b,c
It's a good idea to get used to the GROUP BY syntax, as it's more powerful.
For your query, I'd do it like this:
UPDATE sale...
How do I get list of all tables in a database using TSQL?
...
SQL Server 2000, 2005, 2008, 2012, 2014, 2016, 2017 or 2019:
SELECT * FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_TYPE='BASE TABLE'
To show only tables from a particular database
SELECT TABLE_NAME
FROM <DATABASE_NAME>.INFORMATION_SCHEMA.TABLES
WHERE TABLE_TYPE = 'BASE TABLE'...
How to replace all dots in a string using JavaScript
...
You need to escape the . because it has the meaning of "an arbitrary character" in a regular expression.
mystring = mystring.replace(/\./g,' ')
share
|
improve this answer
|
...
Function to Calculate Median in SQL Server
... in all cases. It also requires SQL 2012 or later.
DECLARE @c BIGINT = (SELECT COUNT(*) FROM dbo.EvenRows);
SELECT AVG(1.0 * val)
FROM (
SELECT val FROM dbo.EvenRows
ORDER BY val
OFFSET (@c - 1) / 2 ROWS
FETCH NEXT 1 + (1 - @c % 2) ROWS ONLY
) AS x;
Of course, just because o...
SELECT * FROM X WHERE id IN (…) with Dapper ORM
...
Dapper supports this directly. For example...
string sql = "SELECT * FROM SomeTable WHERE id IN @ids"
var results = conn.Query(sql, new { ids = new[] { 1, 2, 3, 4, 5 }});
share
|
imp...