大约有 47,000 项符合查询结果（耗时：0.0307秒） [XML]
Is it possible to use the SELECT INTO clause with UNION [ALL]?
...
This works in SQL Server:
SELECT * INTO tmpFerdeen FROM (
SELECT top 100 *
FROM Customers
UNION All
SELECT top 100 *
FROM CustomerEurope
UNION All
SELECT top 100 *
FROM CustomerAsia
UNION All
SELECT top 100 *
FROM CustomerAme...
Is there an equivalent to CTRL+C in IPython Notebook in Firefox to break cells that are running?
...thing that is running in iPython Notebook and you started iPython Notebook from a terminal, you can hit CTRL+C twice in that terminal to interrupt the entire iPython Notebook server. This will stop iPython Notebook alltogether, which means it won't be possible to restart or save your work, so this i...
LISTAGG in Oracle to return distinct values
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19c and later:
select listagg(distinct the_column, ',') within group (order by the_column)
from the_table
18c and earlier:
select listagg(the_column, ',') within group (order by the_column)
from (
select distinct the_column
from t...
Best way to test if a row exists in a MySQL table
...
You could also try EXISTS:
SELECT EXISTS(SELECT * FROM table1 WHERE ...)
and per the documentation, you can SELECT anything.
Traditionally, an EXISTS subquery starts with SELECT *, but it could
begin with SELECT 5 or SELECT column1 or anything ...
What is the difference between float and double?
...le gives 9.000000000000000066 on Mac), but all floating point types suffer from round-off errors, so if precision is very important (e.g. money processing) you should use int or a fraction class.
Furthermore, don't use += to sum lots of floating point numbers, as the errors accumulate quickly. If y...
dd: How to calculate optimal blocksize? [closed]
... pretty solid history of being reliably performant: You can find a message from the Eug-Lug mailing list, circa 2002, recommending a block size of 64K here: http://www.mail-archive.com/eug-lug@efn.org/msg12073.html
For determining THE optimal output block size, I've written the following script tha...
Python: How would you save a simple settings/config file?
... reasons to use a different format.
Write a file like so:
# python 2.x
# from ConfigParser import SafeConfigParser
# config = SafeConfigParser()
# python 3.x
from configparser import ConfigParser
config = ConfigParser()
config.read('config.ini')
config.add_section('main')
config.set('main', 'key...
How can I select from list of values in SQL Server
... would be to use a find an replace with UNION to get the distinct values.
SELECT 1
UNION SELECT 1
UNION SELECT 1
UNION SELECT 2
UNION SELECT 5
UNION SELECT 1
UNION SELECT 6
Applied to your long line of comma delimited text
Find and replace every comma with UNION SELECT
Add a SELECT in front of ...
How does a language expand itself? [closed]
...
A computer is like an onion, it has many many layers, from the inner core of pure hardware to the outermost application layer. Each layer exposes parts of itself to the next outer layer, so that the outer layer may use some of the inner layers functionality.
In the case of e.g....
How to filter SQL results in a has-many-through relation
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Results:
Total runtimes from EXPLAIN ANALYZE.
1) Martin 2: 44.594 ms
SELECT s.stud_id, s.name
FROM student s
JOIN student_club sc USING (stud_id)
WHERE sc.club_id IN (30, 50)
GROUP BY 1,2
HAVING COUNT(*) > 1;
2) Erwin 1: 33.217 ms
SELECT s.stud_id, s.name
FROM student s
JOIN ...