大约有 3,558 项符合查询结果（耗时：0.0412秒） [XML]
How to verify if a file exists in a batch file?
...ndler echo Now Exiting && Exit
if not exist C:\myprogram\html\data.sql Exit
We will take those three files and put it in a temporary place. After deleting the folder, it will restore those three files.
xcopy "test" "C:\temp"
xcopy "test2" "C:\temp"
del C:\myprogram\sync\
xcopy "C:\temp" "...
Overriding a Rails default_scope
... like: def self.random; unscoped.order('rand()'); end unscoped removes ALL sql before it, not just what is listed under default_scope. While technically a correct answer, be careful using unstopped
– Schneems
Dec 25 '11 at 21:58
...
Retrieving the last record in each group - MySQL
...
MySQL 8.0 now supports windowing functions, like almost all popular SQL implementations. With this standard syntax, we can write greatest-n-per-group queries:
WITH ranked_messages AS (
SELECT m.*, ROW_NUMBER() OVER (PARTITIO...
In MySQL queries, why use join instead of where?
...d
From a Performance Perspective:
Where supported (Oracle 9i+, PostgreSQL 7.2+, MySQL 3.23+, SQL Server 2000+), there is no performance benefit to using either syntax over the other. The optimizer sees them as the same query. But more complex queries can benefit from using ANSI-92 syntax:
A...
Create a new database with MySQL Workbench
Being new to MySQL, I have installed the latest version of the MySQL Workbench (5.2.33). I would like to know how you can create a database with this application. In the Overview tab of the SQL editor there are few "MySQL Schema" displayed, are these schemas the existing databases?
...
MySQL root password change
I have been trying to reset my MySQL root password. I have run the mysqld_safe --skip-grant-tables, updated the root password, and checked the user table to make sure it is there. Once restarting the mysql daemon I tried logging in with the new root password that I just set and still get Access de...
Altering a column: null to not null
...
Its strange the MS SQL Management Studio does not allow that option, it brags about "Dropping table ..."
– Sebastian
May 2 '13 at 11:25
...
Is there a query language for JSON?
Is there a (roughly) SQL or XQuery-like language for querying JSON?
22 Answers
22
...
MySQL, update multiple tables with one query
...
If I want to include "LIMIT" to the SQL Query, do I have to say LIMIT 1 or LIMIT 2?
– Bluedayz
Aug 25 '14 at 16:31
2
...
How to dynamically compose an OR query filter in Django?
..._objects)
# sometimes the following is helpful for debugging (returns the SQL statement)
# print queryset.query
share
|
improve this answer
|
follow
|
...