大约有 40,000 项符合查询结果（耗时：0.0418秒） [XML]
How do I copy to the clipboard in JavaScript?
...
document.body.appendChild(textArea);
textArea.focus();
textArea.select();
try {
var successful = document.execCommand('copy');
var msg = successful ? 'successful' : 'unsuccessful';
console.log('Fallback: Copying text command was ' + msg);
} catch (err) {
consol...
List columns with indexes in PostgreSQL
...constraint uk_test3ab unique (a, b));
List indexes and columns indexed:
select
t.relname as table_name,
i.relname as index_name,
a.attname as column_name
from
pg_class t,
pg_class i,
pg_index ix,
pg_attribute a
where
t.oid = ix.indrelid
and i.oid = ix.indexreli...
Extracting specific columns from a data frame
...r package, if your data.frame is called df1:
library(dplyr)
df1 %>%
select(A, B, E)
This can also be written without the %>% pipe as:
select(df1, A, B, E)
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...
Copy tables from one database to another in SQL Server
... server? Use three part naming.
INSERT INTO bar..tblFoobar( *fieldlist* )
SELECT *fieldlist* FROM foo..tblFoobar
This just moves the data. If you want to move the table definition (and other attributes such as permissions and indexes), you'll have to do something else.
...
In SQL, what's the difference between count(column) and count(*)?
...a values(null,1)
insert #bla values(1,null)
insert #bla values(null,null)
select count(*),count(id),count(id2)
from #bla
results
7 3 2
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fo...
mysql update column with value from another table
...
Second possibility is,
UPDATE TableB
SET TableB.value = (
SELECT TableA.value
FROM TableA
WHERE TableA.name = TableB.name
);
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Solutions for INSERT OR UPDATE on SQL Server
...nd PK violations you can use something like this:
begin tran
if exists (select * from table with (updlock,serializable) where key = @key)
begin
update table set ...
where key = @key
end
else
begin
insert into table (key, ...)
values (@key, ...)
end
commit tran
or
begin tran
upda...
“Unresolved inclusion” error with Eclipse CDT for C standard library headers
...lipse, you open the Properties of your project, expand "C/C++ General" and select "Paths and Symbols".
Make sure you have added the include dir for each language you are using. (In my case, I needed to just add it to GNU C++.)
...
What does collation mean?
... is a correctly ordered list:
Namibia
número
ñandú
ñú
obra
ojo
By selecting the correct collation, you get all this done for you, automatically :-)
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...
Can you grab or delete between parentheses in vi/vim?
...motion commands by entering :help various-motions in command mode.
object-select
There is another set of motion commands that you can use in Visual mode to select various text objects.
To solve your specific problem you would do the following:
printf("%3.0f\t%6.1f\n", fahr, ((5.0/9.0) * (fahr-32...