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Want to find records with no associated records in Rails
...u'd want to normalize out the data and index in that case. I might do that by creating a friend_ids hstore or serialized column. Then you could say Person.where(friend_ids: nil)
– Unixmonkey
Dec 20 '16 at 16:02
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WHERE vs HAVING
...ber") after HAVING and not WHERE in MySQL?
WHERE is applied before GROUP BY, HAVING is applied after (and can filter on aggregates).
In general, you can reference aliases in neither of these clauses, but MySQL allows referencing SELECT level aliases in GROUP BY, ORDER BY and HAVING.
And are t...
IN clause and placeholders
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Caused by: android.database.sqlite.SQLiteException: near ",": syntax error (code 1): , while compiling: SELECT url FROM tasks WHERE url=?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,...
Add a column to existing table and uniquely number them on MS SQL Server
...to add a column to an existing legacy database and write a procedure by which I can assign each record a different value. Something like adding a column and autogenerate the data for it.
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Preventing Laravel adding multiple records to a pivot table
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You can check the presence of an existing record by writing a very simple condition like this one :
if (! $cart->items->contains($newItem->id)) {
$cart->items()->save($newItem);
}
Or/and you can add unicity condition in your database, it would throw an...
How to force use of overflow menu on devices with menu button
...wer for the situation of physical menu button.
This is actually prevented by design. According to the Compatibility Section of the Android Design Guide,
"...the action overflow is available from the menu hardware key. The resulting actions popup... is displayed at the bottom of the screen."
You...
Combine two ActiveRecord::Relation objects
... I did this:
name_relation = first_name_relation + last_name_relation
Ruby 1.9, rails 3.2
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SQL Server: SELECT only the rows with MAX(DATE)
... PartCode,
Quantity,
row_number() over(partition by OrderNO order by DateEntered desc) as rn
from YourTable) as T
where rn = 1
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SQL WHERE.. IN clause multiple columns
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@sleske: EXISTS is by far better: see my comments in my answer. And test it first,. @mrdenny: I misread your answer at first, I'd use EXISTS too
– gbn
Jul 16 '09 at 8:17
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MySql Table Insert if not exist otherwise update
... It might be needed to create UNIQUE constraint for Timestamp by using ALTER TABLE AggregatedData ADD UNIQUE (Timestamp)
– Avyakt
Jan 19 '15 at 19:13
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