大约有 44,000 项符合查询结果（耗时：0.0497秒） [XML]
Why there is no ForEach extension method on IEnumerable?
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Couldn't you just use Select instead of your Apply method? It seems to me that applying an action to each element and yielding it is exactly what Select does. E.g. numbers.Select(n => n*2);
– rasmusvhansen
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How to do SELECT COUNT(*) GROUP BY and ORDER BY in Django?
...lvaro has answered the Django's direct equivalent for GROUP BY statement:
SELECT actor, COUNT(*) AS total
FROM Transaction
GROUP BY actor
is through the use of values() and annotate() methods as follows:
Transaction.objects.values('actor').annotate(total=Count('actor')).order_by()
However ...
Split value from one field to two
...);
END$$
DELIMITER ;
you would be able to build your query as follows:
SELECT SPLIT_STR(membername, ' ', 1) as memberfirst,
SPLIT_STR(membername, ' ', 2) as memberlast
FROM users;
If you prefer not to use a user defined function and you do not mind the query to be a bit more verbose, ...
How to stop Visual Studio from opening a file on single click?
...anted to add that the button David is referring to has a tooltip: "Preview Selected Items"
– Bruce van der Kooij
Jan 11 '13 at 9:39
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Naming of ID columns in database tables
...!)and forget to change the alias in the join condition.
So you now have
select t1.field1, t2.field2, t3.field3
from table1 t1
join table2 t2 on t1.id = t2.table1id
join table3 t3 on t1.id = t3.table2id
when you meant
select t1.field1, t2.field2, t3.field3
from table1 t1
join table2 t2 on t1...
Convert a string to int using sql query
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You could use CAST or CONVERT:
SELECT CAST(MyVarcharCol AS INT) FROM Table
SELECT CONVERT(INT, MyVarcharCol) FROM Table
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What does SQL clause “GROUP BY 1” mean?
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SELECT account_id, open_emp_id
^^^^ ^^^^
1 2
FROM account
GROUP BY 1;
In above query GROUP BY 1 refers to the first column in select statement which is
account_id.
You also can speci...
Using IntelliJ to amend git commit message
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Amend is supported: invoke "Commit Changes" and select the checkbox "Amend commit" in the Commit Dialog. Then press "Commit" button, and the commit will be amended to the previous one.
However, the support is limited:
you can't see the details of the commit being amend...
How can I drop all the tables in a PostgreSQL database?
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You can write a query to generate a SQL script like this:
select 'drop table "' || tablename || '" cascade;' from pg_tables;
Or:
select 'drop table if exists "' || tablename || '" cascade;' from pg_tables;
In case some tables are automatically dropped due to cascade option in a...
Indenting code in Sublime text 2?
...gs": { "single_line": false } } will reindent all document without need to select what you want
– Alexis
Apr 22 '15 at 11:43
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