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What columns generally make good indexes?
...earching the results speedily from tables. So it is most important step to select which columns to be indexed. There are two major places where we can consider indexing: columns referenced in the WHERE clause and columns used in JOIN clauses. In short, such columns should be indexed against which yo...
MySQL - SELECT WHERE field IN (subquery) - Extremely slow why?
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Rewrite the query into this
SELECT st1.*, st2.relevant_field FROM sometable st1
INNER JOIN sometable st2 ON (st1.relevant_field = st2.relevant_field)
GROUP BY st1.id /* list a unique sometable field here*/
HAVING COUNT(*) > 1
I think st2.relevant_...
How to automatically navigate to the current class in Intellij Idea Project Tool Window?
...expands to show the currently open class (or file), and this class becomes selected in the tree.
6 Answers
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html (+css): denoting a preferred place for a line break
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Works great - when it is important, that chars like "-" non break. Example: Perikles <span class="avoidwrap">(um&nbsp;500-429&nbsp;v.Chr.)</span>
– Sarah Trees
May 19 '15 at 17:37
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Is it possible to use Java 8 for Android development?
...ce
Click on the Android SDK Manager button which is located on the toolbar
Select Android SDK Build tools Rev. 19.1 and Android Support Library only. Un-select everything else and install these two packages.
If everything goes well, ADT will be up and running.
The installation of the following to...
How to include “zero” / “0” results in COUNT aggregate?
...n outer join for this (and you need to use person as the "driving" table)
SELECT person.person_id, COUNT(appointment.person_id) AS "number_of_appointments"
FROM person
LEFT JOIN appointment ON person.person_id = appointment.person_id
GROUP BY person.person_id;
The reason why this is working, i...
Replace all non-alphanumeric characters in a string
I have a string with which i want to replace any character that isn't a standard character or number such as (a-z or 0-9) with an asterisk. For example, "h^&ell`.,|o w]{+orld" is replaced with "h*ell*o*w*orld". Note that multiple characters such as "^&" get replaced with one asterisk. How would I go...
Spring JPA selecting specific columns
...Spring JPA to perform all database operations. However I don't know how to select specific columns from a table in Spring JPA?
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How to make a select with array contains value clause in psql
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Try
SELECT * FROM table WHERE arr @> ARRAY['s']::varchar[]
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What is the best way to add options to a select from a JavaScript object with jQuery?
What is the best method for adding options to a <select> from a JavaScript object using jQuery?
36 Answers
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