大约有 45,000 项符合查询结果（耗时：0.0272秒） [XML]
Select columns from result set of stored procedure
...stored procedure that returns 80 columns, and 300 rows. I want to write a select that gets 2 of those columns. Something like
...
How does one reorder columns in a data frame?
...
You can also use the subset function:
data <- subset(data, select=c(3,2,1))
You should better use the [] operator as in the other answers, but it may be useful to know that you can do a subset and a column reorder operation in a single command.
Update:
You can also use the select...
How to select all instances of selected region in Sublime Text
Is there a shortcut key or single-step menu option to find and select all instances of a highlighted selection in Sublime Text?
...
How do I cast a string to integer and have 0 in case of error in the cast with PostgreSQL?
...dn't want the overhead of a function. I came up with the following query:
SELECT myfield::integer FROM mytable WHERE myfield ~ E'^\\d+$';
Postgres shortcuts its conditionals, so you shouldn't get any non-integers hitting your ::integer cast. It also handles NULL values (they won't match the regex...
How to submit form on change of dropdown list?
I am creating a page in JSP where I have a dropdown list and once the user selects a value he has to click on the go button and then the value is sent to the Servlet.
...
Any way to make a WPF textblock selectable?
How to allow TextBlock 's text to be selectable?
15 Answers
15
...
How do I get the current time zone of MySQL?
...bal and client-specific time zones can be retrieved like this:
mysql> SELECT @@global.time_zone, @@session.time_zone;
Edit The above returns SYSTEM if MySQL is set to slave to the system's timezone, which is less than helpful. Since you're using PHP, if the answer from MySQL is SYSTEM, you ca...
Fix code indentation in Xcode
...
Before Xcode 9 (for Xcode 9 see default shortcut below)
select text
right-click
there's a "Re-indent selection" item in popup menu
In XCode 4 there is one more step:
select text
right-click
Click on "Structure"
there's a "Re-indent selection" and other options in popup men...
Remove the last character in a string in T-SQL?
... ELSE LEFT(@String, LEN(@String) - 1)
END
) END
SELECT @String
share
|
improve this answer
|
follow
|
...
How to delete from select in MySQL?
...
SELECT (sub)queries return result sets. So you need to use IN, not = in your WHERE clause.
Additionally, as shown in this answer you cannot modify the same table from a subquery within the same query. However, you can either...