大约有 40,000 项符合查询结果（耗时：0.0285秒） [XML]
What's faster, SELECT DISTINCT or GROUP BY in MySQL?
...'t, then use DISTINCT.
GROUP BY in MySQL sorts results. You can even do:
SELECT u.profession FROM users u GROUP BY u.profession DESC
and get your professions sorted in DESC order.
DISTINCT creates a temporary table and uses it for storing duplicates. GROUP BY does the same, but sortes the disti...
android button selector
This is a button selector such that when normal it appears red, when pressed it appears grey.
6 Answers
...
How do I add an existing Solution to GitHub from Visual Studio 2013
...
OK this worked for me.
Open the solution in Visual Studio 2013
Select File | Add to Source Control
Select the Microsoft Git Provider
That creates a local GIT repository
Surf to GitHub
Create a new repository DO NOT SELECT Initialize this repository with a README
That creates an em...
Group by month and year in MySQL
...
I prefer
SELECT
MONTHNAME(t.summaryDateTime) as month, YEAR(t.summaryDateTime) as year
FROM
trading_summary t
GROUP BY EXTRACT(YEAR_MONTH FROM t.summaryDateTime) DESC";
...
How do you open an SDF file (SQL Server Compact Edition)? [closed]
...t intuitive:
Open SQL Server Management Studio, or if it's running select File -> Connect Object Explorer...
In the Connect to Server dialog change Server type to SQL Server Compact Edition
From the Database file dropdown select < Browse for more...>
Open your SDF file.
...
Generating a random & unique 8 character string using MySQL
...umn:
INSERT INTO vehicles VALUES (blah); -- leaving out the number plate
SELECT @lid:=LAST_INSERT_ID();
UPDATE vehicles SET numberplate=concat(
substring('ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789', rand(@seed:=round(rand(@lid)*4294967296))*36+1, 1),
substring('ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789'...
Selecting last element in JavaScript array [duplicate]
...gth less 1.
Mozilla Docs on Slice
Performance of the various methods for selecting last array element
share
|
improve this answer
|
follow
|
...
How to search a string in multiple files and return the names of files in Powershell?
...location of the files that contain your pattern:
Get-ChildItem -Recurse | Select-String "dummy" -List | Select Path
share
|
improve this answer
|
follow
|
...
How do I check if a column is empty or null in MySQL?
...
This will select all rows where some_col is NULL or '' (empty string)
SELECT * FROM table WHERE some_col IS NULL OR some_col = '';
share
|
...
SQL: How to properly check if a record exists
...
It's better to use either of the following:
-- Method 1.
SELECT 1
FROM table_name
WHERE unique_key = value;
-- Method 2.
SELECT COUNT(1)
FROM table_name
WHERE unique_key = value;
The first alternative should give you no result or one result, the second count should be zero or on...