大约有 40,000 项符合查询结果（耗时：0.0402秒） [XML]
How to clear variables in ipython?
...r @ErdemKAYA comment.
To erase a variable, use the magic command:
%reset_selective <regular_expression>
The variables that are erased from the namespace are the one matching the given <regular_expression>.
Therefore
%reset_selective -f a
will erase all the variables containing a...
PostgreSQL wildcard LIKE for any of a list of words
... can use Postgres' SIMILAR TO operator which supports alternations, i.e.
select * from table where lower(value) similar to '%(foo|bar|baz)%';
share
|
improve this answer
|
...
How can I see the SQL that will be generated by a given ActiveRecord query in Ruby on Rails
... write a plugin that would do something like: SampleModel.find(:all, :select => "DISTINCT(*)", :conditions => ["date > #{self.date}"], :limit => 1, :order => 'date', :group => "date").show_generated_sql and have this call the construct_finder_sql method.
...
How do I declare and assign a variable on a single line in SQL
...
You can also initialize from a select statement, eg: declare @eid uniqueidentifier = (select top 1 id from t_Event)
– Damien Sawyer
Sep 8 '16 at 20:32
...
How to swap the buffers in 2 windows emacs
...
If you just want to swap windows (independent on the selected one), you can use the following (defun win-swap () "Swap windows using buffer-move.el" (interactive) (if (null (windmove-find-other-window 'right)) (buf-move-left) (buf-move-right)))
...
Where are my postgres *.conf files?
...alives_idle = 0 # TCP_KEEPIDLE, in seconds;
# 0 selects the system default
#tcp_keepalives_interval = 0 # TCP_KEEPINTVL, in seconds;
# 0 selects the system default
#tcp_keepalives_count = 0 # TCP_KEEPCNT;
# 0 selects the...
What's the Point of Multiple Redis Databases?
...e instances lets you take advantage of multiple cores. If you use database selection you will have to refactor when upgrading. Monitoring and managing multiple instances is not difficult nor painful.
Indeed, you would get far better metrics on each db by segregation based on instance. Each instanc...
How to find the size of an array in postgresql
...ikely) and are running PostgreSQL 9.4 or higher, you can use cardinality:
SELECT cardinality(id) FROM example;
share
|
improve this answer
|
follow
|
...
COALESCE Function in TSQL
...ks perfectly & gives a good visual explanation of how COALESCE works:
SELECT Name, Class, Color, ProductNumber,
COALESCE(Class, Color, ProductNumber) AS FirstNotNull
FROM Production.Product
share
|
...
Python: Tuples/dictionaries as keys, select, sort
...d like to organize them in a data structure in Python that allows for easy selection and sorting. My idea was to put them into a dictionary with tuples as keys, e.g.,
...