大约有 41,000 项符合查询结果（耗时：0.0314秒） [XML]
How to concatenate strings of a string field in a PostgreSQL 'group by' query?
...at the question asked for, even letting you specify the delimiter string:
SELECT company_id, string_agg(employee, ', ')
FROM mytable
GROUP BY company_id;
Postgres 9.0 also added the ability to specify an ORDER BY clause in any aggregate expression; otherwise, the order is undefined. So you can no...
What is the format specifier for unsigned short int?
...ntf" short ints because they are automatically promoted to ints (just like chars).
– Alexey Frunze
Jan 2 '12 at 11:00
2
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The SQL OVER() clause - when and why is it useful?
...ated values and then join it back to the original rowset, i.e. like this:
SELECT
orig.[Partition],
orig.Value,
orig.Value * 100.0 / agg.TotalValue AS ValuePercent
FROM OriginalRowset orig
INNER JOIN (
SELECT
[Partition],
SUM(Value) AS TotalValue
FROM OriginalRowset
G...
Clear form fields with jQuery
...
A small tip: this selector won't select input elements that are relying on the implicit type=text, you must explicitly include the type=text on your markup. That may be obvious, but it wasn't to me, just now :-)
– Elbin
...
How do you use script variables in psql?
...t myvariable value
... and can then be substituted, for example, as ...
SELECT * FROM :myvariable.table1;
... or ...
SELECT * FROM table1 WHERE :myvariable IS NULL;
edit: As of psql 9.1, variables can be expanded in quotes as in:
\set myvariable value
SELECT * FROM table1 WHERE column1 ...
How can I check whether a radio button is selected with JavaScript?
...when one of the fields is null. How can I check whether a radio button is selected?
28 Answers
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XPath to select multiple tags
...l-name()='e']
is both too-long and incorrect. This XPath expression will select nodes like:
OhMy:c
NotWanted:d
QuiteDifferent:e
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Nested select statement in SQL Server
...
You need to alias the subquery.
SELECT name FROM (SELECT name FROM agentinformation) a
or to be more explicit
SELECT a.name FROM (SELECT name FROM agentinformation) a
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Cannot truncate table because it is being referenced by a FOREIGN KEY constraint?
...
IF OBJECT_ID('tempdb..#FKs') IS NOT NULL
DROP TABLE #FKs
-- GET FKs
SELECT ROW_NUMBER() OVER (ORDER BY OBJECT_NAME(parent_object_id), clm1.name) as ID,
OBJECT_NAME(constraint_object_id) as ConstraintName,
OBJECT_NAME(parent_object_id) as TableName,
clm1.name as ColumnName...
Consistency of hashCode() on a Java string
....x the hashCode
function for long Strings worked by
sampling every nth character. This
pretty well guaranteed you would have
many Strings hashing to the same
value, thus slowing down Hashtable
lookup. In JDK 1.2 the function has
been improved to multiply the result
so far by 31 then ...