大约有 47,000 项符合查询结果（耗时：0.0402秒） [XML]
Find rows with multiple duplicate fields with Active Record, Rails & Postgres
...
Tested & Working Version
User.select(:first,:email).group(:first,:email).having("count(*) > 1")
Also, this is a little unrelated but handy. If you want to see how times each combination was found, put .size at the end:
User.select(:first,:email).gro...
Missing Push Notification Entitlement
...from the answer given by @Vaiden, in Xcode 8 you can resolve this issue by selecting the target and clicking the "Fix issue". Of course, you'll still need to set up push notifications in the Apple Developer portal (you can simplify the process a little by using the new "Automatically manage signing"...
What type of hash does WordPress use?
...have access to the DB, using MyPHPAdmin you can change the PW to "MyPass", select MD5 in the "Function" dropdown and it will save as a straight MD5. Sign into Wordpress, and it will change it to the "salted" version with the $P$B__/ added.
– BillyNair
Oct 26 '1...
PostgreSQL “DESCRIBE TABLE”
... 'table' or \ds 'sequence' and so on)
The SQL standard way, as shown here:
select column_name, data_type, character_maximum_length, column_default, is_nullable
from INFORMATION_SCHEMA.COLUMNS where table_name = '<name of table>';
It's supported by many db engines.
...
Can I write into the console in a unit test? If yes, why doesn't the console window open?
...
In V2017 (Community), go to "test explorer", select the test result item in the list, then click on the link "output" on the other window (test result window?). Since it will probably be truncated, use the "copy all" and past somewhere else.
– heri...
C# SQL Server - Passing a list to a stored procedure
...StringList READONLY
AS
BEGIN
-- Just return the items we passed in
SELECT l.Item FROM @list l;
END
Finally here's some sql to use it in c#:
using (var con = new SqlConnection(connstring))
{
con.Open();
using (SqlCommand cmd = new SqlCommand("exec sp_UseStringList @list", con))
...
Copy table without copying data
...
Try:
CREATE TABLE foo SELECT * FROM bar LIMIT 0
Or:
CREATE TABLE foo SELECT * FROM bar WHERE 1=0
share
|
improve this answer
|
...
Add 2 hours to current time in MySQL?
...
SELECT *
FROM courses
WHERE DATE_ADD(NOW(), INTERVAL 2 HOUR) > start_time
See Date and Time Functions for other date/time manipulation.
share
...
MYSQL OR vs IN performance
...for future Googlers. Total count of returned results is 7264 out of 10000
SELECT * FROM item WHERE id = 1 OR id = 2 ... id = 10000
This query took 0.1239 seconds
SELECT * FROM item WHERE id IN (1,2,3,...10000)
This query took 0.0433 seconds
IN is 3 times faster than OR
...
Create batches in linq
... int maxItems)
{
return items.Select((item, inx) => new { item, inx })
.GroupBy(x => x.inx / maxItems)
.Select(g => g.Select(x => x.item));
}
}
and the usage would be:
List<int> list = new L...