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编译器内部的秘密--微软的编译器是如何解析Try/Catch/Throw的 - C/C++ - 清...
...是一篇介绍如何在x86架构上详细地实现异常处理(exception handling)的手册，只是一篇入门的讨论性文章。本文只是讨论一些处理步骤在理论上应该如何实现，其具体的实现步骤可能跟文章所讨论的并不一致。原文译自：http://www.codep...
jQuery - getting custom attribute from selected option
...
You're adding the event handler to the <select> element.
Therefore, $(this) will be the dropdown itself, not the selected <option>.
You need to find the selected <option>, like this:
var option = $('option:selected', this).attr('mytag');
...
Should MySQL have its timezone set to UTC?
...the timezone will not change the stored datetime or
timestamp, but it will select a different datetime from
timestamp columns
Warning! UTC has leap seconds, these look like '2012-06-30 23:59:60' and can
be added randomly, with 6 months prior notice, due to the slowing of
the earths rotation
GMT con...
Generate a random number in the range 1 - 10
... 1 and 10 you mean any float that is >= 1 and < 10, then it's easy:
select random() * 9 + 1
This can be easily tested with:
# select min(i), max(i) from (
select random() * 9 + 1 as i from generate_series(1,1000000)
) q;
min | max
-----------------+------------------...
How do you find the row count for all your tables in Postgres
...th their own tradeoffs.
If you want a true count, you have to execute the SELECT statement like the one you used against each table. This is because PostgreSQL keeps row visibility information in the row itself, not anywhere else, so any accurate count can only be relative to some transaction. Yo...
How to send data to local clipboard from a remote SSH session
...
I often to this in vim. To do so, select what you want to copy in visual mode, then type: :'<,'>w !ssh desktop pbcopy
– Mike Brennan
Nov 30 '12 at 5:04
...
SQL Server SELECT LAST N Rows
...d database... Now let us retrieve the Last 5 orders placed by Employee 5:
SELECT ORDERID, CUSTOMERID, OrderDate
FROM
(
SELECT ROW_NUMBER() OVER (PARTITION BY EmployeeID ORDER BY OrderDate DESC) AS OrderedDate,*
FROM Orders
) as ordlist
WHERE ordlist.EmployeeID = 5
AND ordlist.OrderedDate &...
SQL Server dynamic PIVOT query?
... @cols AS NVARCHAR(MAX),
@query AS NVARCHAR(MAX);
SET @cols = STUFF((SELECT distinct ',' + QUOTENAME(c.category)
FROM temp c
FOR XML PATH(''), TYPE
).value('.', 'NVARCHAR(MAX)')
,1,1,'')
set @query = 'SELECT date, ' + @cols + ' from
(...
SQL Server : Columns to Rows
...
You can use the UNPIVOT function to convert the columns into rows:
select id, entityId,
indicatorname,
indicatorvalue
from yourtable
unpivot
(
indicatorvalue
for indicatorname in (Indicator1, Indicator2, Indicator3)
) unpiv;
Note, the datatypes of the columns you are unpivoting mus...
Efficient SQL test query or validation query that will work across all (or most) databases
...er a little bit of research along with help from some of the answers here:
SELECT 1
H2
MySQL
Microsoft SQL Server (according to NimChimpsky)
PostgreSQL
SQLite
SELECT 1 FROM DUAL
Oracle
SELECT 1 FROM any_existing_table WHERE 1=0
or
SELECT 1 FROM INFORMATION_SCHEMA.SYSTEM_USERS
or
CALL NOW()
HS...