大约有 6,200 项符合查询结果（耗时：0.0131秒） [XML]
Switch on Enum in Java [duplicate]
...r speed, the switch statement approach might be faster because it's just a table lookup in the bytecode. With your approach, you have to push a new function onto the stack. It's a micro-optimization, but if speed is super important it's something to keep in mind.
– DIMMSum
...
ASP.NET MVC 5 - Identity. How to get current ApplicationUser
... having an extra context for starters, but going forward the user database tables change (3 times in the past 2 years) but the API is consistent. For example the users table is now called AspNetUsers in Identity Framework, and the names of several primary key fields kept changing, so the code in sev...
postgresql COUNT(DISTINCT …) very slow
...
You can use this:
SELECT COUNT(*) FROM (SELECT DISTINCT column_name FROM table_name) AS temp;
This is much faster than:
COUNT(DISTINCT column_name)
share
|
improve this answer
|
...
SQLite string contains other string query
...
Using LIKE:
SELECT *
FROM TABLE
WHERE column LIKE '%cats%' --case-insensitive
share
|
improve this answer
|
follow
...
How to convert local time string to UTC?
... platform. You could use tzlocal.get_localzone() to provide tzdata in a portable way. (2) fromtimestamp(t, tz) may fail for non-pytz timezones. (3) datetime(*struct_time[:6]) you are missing *. (4) timegm(), utctimetuple(), struct_time -based solutions drop fractions of a second. You could use an e...
How to best display in Terminal a MySQL SELECT returning too many fields?
...erminate the query with \G in place of ;. For example:
SELECT * FROM sometable\G
This query displays the rows vertically, like this:
*************************** 1. row ***************************
Host: localhost
Db: mydatabase1
User: myuser1
...
Use variable with TOP in select statement in SQL Server without making it dynamic [duplicate]
...'s possible to use a variable in the top clause.
select top (@top) * from tablename
share
|
improve this answer
|
follow
|
...
On duplicate key ignore? [duplicate]
...).
Instead, since in your example tag is the unique key, use:
INSERT INTO table_tags (tag) VALUES ('tag_a'),('tab_b'),('tag_c') ON DUPLICATE KEY UPDATE tag=tag;
on duplicate key produces:
Query OK, 0 rows affected (0.07 sec)
...
Javascript. Assign array values to multiple variables? [duplicate]
...t in languages such as Perl and Python.
Unfortunately, according to this table of versions, JavaScript 1.7 has not been implemented in Chrome. But it should be there in:
FireFox 2.0+
IE 9
Opera 11.50.
Try it for yourself in this jsfiddle: http://jsfiddle.net/uBReg/
I tested this on Chrome (f...
SQL WITH clause example [duplicate]
...me assigned to the sub-query is treated as though it was an inline view or table. The SQL WITH clause is basically a drop-in replacement to the normal sub-query.
Syntax For The SQL WITH Clause
The following is the syntax of the SQL WITH clause when using a single sub-query alias.
WITH <alias_n...