大约有 47,000 项符合查询结果（耗时：0.0329秒） [XML]
MySQL: Set user variable from result of query
...need to move the variable assignment into the query:
SET @user := 123456;
SELECT @group := `group` FROM user WHERE user = @user;
SELECT * FROM user WHERE `group` = @group;
Test case:
CREATE TABLE user (`user` int, `group` int);
INSERT INTO user VALUES (123456, 5);
INSERT INTO user VALUES (111111...
postgresql - sql - count of `true` values
...
SELECT COALESCE(sum(CASE WHEN myCol THEN 1 ELSE 0 END),0) FROM <table name>
or, as you found out for yourself:
SELECT count(CASE WHEN myCol THEN 1 END) FROM <table name>
...
How can prepared statements protect from SQL injection attacks?
...ample shows it (all examples in PHP/Mysql):
$expected_data = 1;
$query = "SELECT * FROM users where id=$expected_data";
will produce a regular query
SELECT * FROM users where id=1
while this code
$spoiled_data = "1; DROP TABLE users;"
$query = "SELECT * FROM users where id=$spoiled_da...
Using column alias in WHERE clause of MySQL query produces an error
... though, by putting the expression directly into the WHERE x IN y clause:
SELECT `users`.`first_name`,`users`.`last_name`,`users`.`email`,SUBSTRING(`locations`.`raw`,-6,4) AS `guaranteed_postcode`
FROM `users` LEFT OUTER JOIN `locations`
ON `users`.`id` = `locations`.`user_id`
WHERE SUBSTRING(`loca...
Select N random elements from a List in C#
I need a quick algorithm to select 5 random elements from a generic list. For example, I'd like to get 5 random elements from a List<string> .
...
How to generate an entity-relationship (ER) diagram using Oracle SQL Developer
... as follows:
Click File → Data Modeler → Import → Data Dictionary.
Select a DB connection (add one if none).
Click Next.
Check one or more schema names.
Click Next.
Check one or more objects to import.
Click Next.
Click Finish.
The ERD is displayed.
Export the diagram as follows:
Click ...
How to have a default option in Angular.js select box
...
You can simply use ng-init like this
<select ng-init="somethingHere = options[0]"
ng-model="somethingHere"
ng-options="option.name for option in options">
</select>
...
Add a number to each selection in Sublime Text 2, incremented once per selection
...
M represents the step size which will be added to the index for
each selection.
P must be > 0 and will be used to pad the index with
leading zeroes.
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Prevent text selection after double click
...lick event on a span in my web app. A side-effect is that the double click selects text on the page. How can I prevent this selection from happening?
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Finding duplicate rows in SQL Server
...abase of organizations, and there are many duplicate rows. I want to run a select statement to grab all of these and the amount of dupes, but also return the ids that are associated with each organization.
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