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Is the primary key automatically indexed in MySQL?
...m/doc/refman/5.5/en/optimizing-primary-keys.html
The primary key for a table represents the column or set of columns
that you use in your most vital queries. It has an associated index,
for fast query performance
For MySQL 5.0 reference see: http://dev.mysql.com/doc/refman/5.0/en/mysql-ind...
In a bootstrap responsive page how to center a div
...http://getbootstrap.com/dist/css/bootstrap.css');
html, body, .container-table {
height: 100%;
}
.container-table {
display: table;
}
.vertical-center-row {
display: table-cell;
vertical-align: middle;
}
<script src="http://cdnjs.cloudflare.com/ajax/libs/twitter-bootst...
Adding a column to an existing table in a Rails migration
...e the add_column line completely (that code is trying to add a column to a table, before the table has been created, and your table creation code has already been updated to include a t.string :email anyway).
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Limiting the number of records from mysqldump?
...atabase
Of course, that would give you the first million rows from every table.
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How do I get SUM function in MySQL to return '0' if no values are found?
...Use COALESCE to avoid that outcome.
SELECT COALESCE(SUM(column),0)
FROM table
WHERE ...
To see it in action, please see this sql fiddle: http://www.sqlfiddle.com/#!2/d1542/3/0
More Information:
Given three tables (one with all numbers, one with all nulls, and one with a mixture):
SQL Fidd...
Postgres dump of only parts of tables for a dev snapshot
...
On your larger tables you can use the COPY command to pull out subsets...
COPY (SELECT * FROM mytable WHERE ...) TO '/tmp/myfile.tsv'
COPY mytable FROM 'myfile.tsv'
https://www.postgresql.org/docs/current/static/sql-copy.html
You shoul...
How to quickly edit values in table in SQL Server Management Studio?
...> "Edit Top 200 Rows" from Object Explorer, is there a quick way to open a table in Edit mode where I can just quickly modify the value of a cell?
...
Mysql order by specific ID values
...and FIELD function.
See http://lists.mysql.com/mysql/209784
SELECT * FROM table ORDER BY FIELD(ID,1,5,4,3)
It uses Field() function, Which "Returns the index (position) of str in the str1, str2, str3, ... list. Returns 0 if str is not found" according to the documentation. So actually you sort th...
Have a reloadData for a UITableView animate when changing
I have a UITableView that has two modes. When we switch between the modes I have a different number of sections and cells per section. Ideally, it would do some cool animation when the table grows or shrinks.
...
Deleting Row in SQLite in Android
...tion, but I'm new to SQLite and I can't seem to figure this out. I have 1 table that has columns KEY_ROWID , KEY_NAME , KAY_LATITUDE , and KEY_LONGITUDE . I want the user to be able to select one and delete it; Can anyone give me a direction to start in? My question is in the actual deletion ...