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How to create an object for a Django model with a many to many field?
...e_object.users.add(1,2)
Update: After reading the saverio's answer, I decided to investigate the issue a bit more in depth. Here are my findings.
This was my original suggestion. It works, but isn't optimal. (Note: I'm using Bars and a Foo instead of Users and a Sample, but you get the idea).
ba...
MySQL ON DUPLICATE KEY - last insert id?
...e.html
At the bottom of the page they explain how you can make LAST_INSERT_ID meaningful for updates by passing an expression to that MySQL function.
From the MySQL documentation example:
If a table contains an AUTO_INCREMENT column and INSERT ... UPDATE inserts a row, the LAST_INSERT_ID() func...
How to get cumulative sum
...
select t1.id, t1.SomeNumt, SUM(t2.SomeNumt) as sum
from @t t1
inner join @t t2 on t1.id >= t2.id
group by t1.id, t1.SomeNumt
order by t1.id
SQL Fiddle example
Output
| ID | SOMENUMT | SUM |
-----------------------
| 1 | 1...
Efficiently convert rows to columns in sql server
... from yourtable
group by ColumnName, id
order by id
FOR XML PATH(''), TYPE
).value('.', 'NVARCHAR(MAX)')
,1,1,'')
set @query = N'SELECT ' + @cols + N' from
(
select value, Column...
How do I find a “gap” in running counter with SQL?
...
In MySQL and PostgreSQL:
SELECT id + 1
FROM mytable mo
WHERE NOT EXISTS
(
SELECT NULL
FROM mytable mi
WHERE mi.id = mo.id + 1
)
ORDER BY
id
LIMIT 1
In SQL Server:
SELECT TOP 1
id + 1
FR...
Does MongoDB's $in clause guarantee order
...y have two options.
So let's say that you were matching on the values of _id in your documents with an array that is going to be passed in to the $in as [ 4, 2, 8 ].
Approach using Aggregate
var list = [ 4, 2, 8 ];
db.collection.aggregate([
// Match the selected documents by "_id"
{...
get an element's id
Is there another way to get an DOM element's ID?
8 Answers
8
...
Can multiple different HTML elements have the same ID if they're different elements?
Can multiple HTML elements have the same ID if they're of different element types? Is a scenario like this valid? Eg:
16 An...
How to specify id when uses include in layout xml file
...ml file, I have included other layout xml file (each
with a different android id).
11 Answers
...
MySQL INNER JOIN select only one row from second table
...
You need to have a subquery to get their latest date per user ID.
SELECT a.*, c.*
FROM users a
INNER JOIN payments c
ON a.id = c.user_ID
INNER JOIN
(
SELECT user_ID, MAX(date) maxDate
FROM payments
GROUP BY user_ID
) b ON c.user_ID = b....