大约有 30,000 项符合查询结果（耗时：0.0153秒） [XML]
Rails where condition using NOT NIL
..., so you really should just use the joins predicate:
Foo.joins(:bar)
Select * from Foo Inner Join Bars ...
But, for the record, if you want a "NOT NULL" condition simply use the not predicate:
Foo.includes(:bar).where.not(bars: {id: nil})
Select * from Foo Left Outer Join Bars on .. WHERE ...
Installing CocoaPods: no response
...rnet. you can check this by following below steps:
Open Activity Monitor
Select Network option
Check below Google Chrome. (ruby downloading)
share
|
improve this answer
|
...
MySQL: determine which database is selected?
After calling mysql_select_db to grab a database, is there any way to later output the name of the database that is currently selected? This seems very basic but I couldn't find anything on php.net or stackoverflow (all results are for "no database selected").
...
How do you effectively model inheritance in a database?
...etimes needed, when you want to load a list of all records (without doing select on each and every child table). One way to handle this, is to have one column representing the type of the child class (similar to the rowType field in the TPH), so mixing the TPT and TPH somehow.
Say we want to des...
How much is the overhead of smart pointers compared to normal pointers in C++?
...o overhead in the destructor. It does exactly the same as you would with a raw pointer.
– R. Martinho Fernandes
Dec 15 '14 at 11:22
...
What's the best manner of implementing a social activity stream? [closed]
...
Smallish in this case is such that "select * from events where event.is visible for this user" returns a result in less than a second or two- figure a few hundred thousand rows worth of events.
– Tim Howland
May 26 '09 at ...
Distinct not working with LINQ to Objects
...ey were hit during the foreach loop. This is because the var temp = books.SelectMany(book => book.Authors).Distinct(); returns an IEnumerable, meaning that the request is not executed right away, it is only executed when the data is used. If you would like an example of this firing right away, ...
fastest MD5 Implementation in JavaScript
...
While selecting library it's also important to see if it supports modern frameworks such as Bower, passes jslint, supports plugin model for JQuery or module systems such as AMD/RequireJS in addition to being in active development a...
How to post pictures to instagram using API
...cking on chrome.
From top right corener menu drop down on developer tools, select more tool.
Further select network conditions.
In the network selection section, see the second section there named user agent.
Uncheck select automatically, and select chrome for Android from the list of given user age...
Difference between CLOCK_REALTIME and CLOCK_MONOTONIC?
...
Note that on newer kernels, CLOCK_MONOTONIC_RAW is available which is even better (no NTP adjustments).
– Joseph Garvin
Aug 20 '12 at 13:59
14
...