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Test for non-zero length string in Bash: [ -n “$var” ] or [ “$var” ]
...on that shows more differences between [ (aka test) and [[.
The following table shows that whether a variable is quoted or not, whether you use single or double brackets and whether the variable contains only a space are the things that affect whether using a test with or without -n/-z is suitable ...
How to express a NOT IN query with ActiveRecord/Rails?
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Using Arel:
topics=Topic.arel_table
Topic.where(topics[:forum_id].not_in(@forum_ids))
or, if preferred:
topics=Topic.arel_table
Topic.where(topics[:forum_id].in(@forum_ids).not)
and since rails 4 on:
topics=Topic.arel_table
Topic.where.not(topics[:f...
How to get record created today by rails activerecord?
...ion suggested in the accepted answer can cause performance issues when the table size grows.
Typically, if you perform lookups based on created_at column, add an index on the table in your migration file.
add_index :posts, :created_at
Now, to lookup records created today:
Rails 3/4
Post.where...
Reset the database (purge all), then seed a database
Is there a rake command to wipe out the data in the database tables?
6 Answers
6
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Is the NOLOCK (Sql Server hint) bad practice?
...dated at the same time another process may be selecting data from the same table. If this happens a lot then there's a high probability of deadlocks unless you use a database mode such as READ COMMITED SNAPSHOT.
I have since changed my perspective on the use of NOLOCK after witnessing how it can i...
In jQuery, how do I get the value of a radio button when they all have the same name?
...dflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<table>
<tr>
<td>Sales Promotion</td>
<td><input type="radio" name="q12_3" value="1">1</td>
<td><input type="radio" name="q12_3" value="2">2</td>
...
Should I use 'border: none' or 'border: 0'?
...they behave in different ways when combined with other rules.
Borders in a table context in collapsing border model
When a table is rendered using border-collapse: collapse, then each rendered border is shared between multiple elements (inner borders are shared among as neighbor cells; outer borders...
SQL Server equivalent to Oracle's CREATE OR REPLACE VIEW
...ISTS' to check if the view exists and drop if it does.
IF EXISTS (SELECT TABLE_NAME FROM INFORMATION_SCHEMA.VIEWS
WHERE TABLE_NAME = 'MyView')
DROP VIEW MyView
GO
CREATE VIEW MyView
AS
....
GO
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Detect if value is number in MySQL
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This should work in most cases.
SELECT * FROM myTable WHERE concat('',col1 * 1) = col1
It doesn't work for non-standard numbers like
1e4
1.2e5
123. (trailing decimal)
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Best way to do nested case statement logic in SQL Server
... NULL
END AS 'calculatedcol1',
col4,
col5 -- etc
FROM table
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