大约有 415 项符合查询结果（耗时：0.0294秒） [XML]
Index on multiple columns in Ruby on Rails
... its columns in sequence starting at the beginning. i.e. if you index on [:user_id, :article_id], you can perform a fast query on user_id or user_id AND article_id, but NOT on article_id.
Your migration add_index line should look something like this:
add_index :user_views, [:user_id, :article_id...
How to get ID of the last updated row in MySQL?
...sers set status = 'processing' where status = 'pending'
and last_insert_id(user_id)
limit 1
The addition of last_insert_id(user_id) in the where clause is telling MySQL to set its internal variable to the ID of the found row. When you pass a value to last_insert_id(expr) like this, it ends up ret...
Create unique constraint with null columns
... two partial indexes:
CREATE UNIQUE INDEX favo_3col_uni_idx ON favorites (user_id, menu_id, recipe_id)
WHERE menu_id IS NOT NULL;
CREATE UNIQUE INDEX favo_2col_uni_idx ON favorites (user_id, recipe_id)
WHERE menu_id IS NULL;
This way, there can only be one combination of (user_id, recipe_id) whe...
Is it possible to send an array with the Postman Chrome extension?
...t-Type as application/json in Headers tab.
Here is example for raw data {"user_ids": ["123" "233"]}, don't forget the quotes!
If you are using the postman REST client you have to use the method I described above because passing data as raw (json) won't work. There is a bug in the postman REST cli...
Fastest way to check if a string is JSON in PHP?
... OK
return $result;
}
Testing with Valid JSON INPUT
$json = '[{"user_id":13,"username":"stack"},{"user_id":14,"username":"over"}]';
$output = json_validate($json);
print_r($output);
Valid OUTPUT
Array
(
[0] => stdClass Object
(
[user_id] => 13
...
In SQL, how can you “group by” in ranges?
... as [score range], count(*) as [number of occurrences]
from (
select user_id,
case when score >= 0 and score< 10 then '0-9'
when score >= 10 and score< 20 then '10-19'
else '20-99' end as range
from scores) t
group by t.range
...
Relational table naming convention [closed]
...ll the time, and you want keys to stand out from data columns. Always use user_id, never id.
Note that this is not a table name used as a prefix, but a proper descriptive name for the component of the key: user_id is the column that identifies an user, not the id of the user table.
(Except of...
Rails params explained?
...user's browser requested
http://www.example.com/?vote[item_id]=1&vote[user_id]=2
then params[:vote] would be a hash, params[:vote][:item_id] would be "1" and params[:vote][:user_id] would be "2".
The Ruby on Rails params are the equivalent of the $_REQUEST array in PHP.
...
Using column alias in WHERE clause of MySQL query produces an error
...e`
FROM `users` LEFT OUTER JOIN `locations`
ON `users`.`id` = `locations`.`user_id`
WHERE SUBSTRING(`locations`.`raw`,-6,4) NOT IN #this is where the fake col is being used
(
SELECT `postcode` FROM `postcodes` WHERE `region` IN
(
'australia'
)
)
However, I guess this is very inefficient, sinc...
MySQL COUNT DISTINCT
...
Select
Count(Distinct user_id) As countUsers
, Count(site_id) As countVisits
, site_id As site
From cp_visits
Where ts >= DATE_SUB(NOW(), INTERVAL 1 DAY)
Group By site_id
...