大约有 40,000 项符合查询结果（耗时：0.0432秒） [XML]
Difference between left join and right join in SQL Server [duplicate]
...ed completely interchangeable. Try however Table2 left join Table1 (or its identical pair, Table1 right join Table2) to see a difference. This query should give you more rows, since Table2 contains a row with an id which is not present in Table1.
...
Moving from CVS to Git: $Id$ equivalent?
...t's say that packaged version was 2.2-12-g6c4ae7a (not a release, but a valid version).
You can now see exactly how far behind you are (4 commits), and you can see exactly which 4 commits:
# The RHS of the .. can be origin/master or empty, or whatever you want.
% git log --pretty=format:"%h %an %s...
MySQL join with where clause
...N user_category_subscriptions ON
user_category_subscriptions.category_id = categories.category_id
and user_category_subscriptions.user_id =1
See, with an inner join, putting a clause in the join or the where is equivalent. However, with an outer join, they are vastly different.
As a join...
What are the details of “Objective-C Literals” mentioned in the Xcode 4.4 release notes?
...23.45;
number = @YES;
[Edit]
zxoq at http://news.ycombinator.com/item?id=3672744 has added more interesting new subscripting. (Added with literals):
arr[1] === [arr objectAtIndex:1]
dict[@"key"] === [dict objectForKey:@"key"]
[Edit 2]
The new ObjC literals were discussed in multiple ...
Foreign key constraint may cause cycles or multiple cascade paths?
...lter your design (or doing so would compromise things) then you should consider using triggers as a last resort.
FWIW resolving cascade paths is a complex problem. Other SQL products will simply ignore the problem and allow you to create cycles, in which case it will be a race to see which will ove...
How can you represent inheritance in a database?
...--+---------------------+----------+----------------+------------------+
| id | date_issued | type | vehicle_reg_no | property_address |
+------+---------------------+----------+----------------+------------------+
| 1 | 2010-08-20 12:00:00 | MOTOR | 01-A-04004 | NULL ...
How to do constructor chaining in C#
...ou use standard syntax (using this like a method) to pick the overload, inside the class:
class Foo
{
private int id;
private string name;
public Foo() : this(0, "")
{
}
public Foo(int id, string name)
{
this.id = id;
this.name = name;
}
pub...
Oracle: how to UPSERT (update or insert into a table?)
... and the update where another process could successfully fire a delete. I did however use this pattern on a table that never has deletes fired against it.
– chotchki
Sep 29 '11 at 22:50
...
Split column at delimiter in data frame [duplicate]
...t some more magic to make it into a data.frame.
I added a "x|y" line to avoid ambiguities:
df <- data.frame(ID=11:13, FOO=c('a|b','b|c','x|y'))
foo <- data.frame(do.call('rbind', strsplit(as.character(df$FOO),'|',fixed=TRUE)))
Or, if you want to replace the columns in the existing data.fram...
Set value of hidden field in a form using jQuery's “.val()” doesn't work
I've been trying to set the value of a hidden field in a form using jQuery, but without success.
16 Answers
...