MySQL

mysql count duplicates

If you want the count of everything, not just the tuples with duplicates, then eliminate the HAVING line, as that’ll filter out anything that doesn’t have duplicates.

Cannot connect to Database server (mysql workbench)

The issue is likely due to socket authentication being enabled for the root user by default when no password is set, during the upgrade to ubuntu 16.04. The solution is to revert back to native password authentication. You can do this by logging in to MySQL using socket authentication by doing: Once logged in: which … Read more

Getting java.sql.SQLException: Operation not allowed after ResultSet closed

The problem is with the way you fetch data in getStuff(). Each time you visit getStuff() you obtain a fresh ResultSet but you don’t close it. This violates the expectation of the Statement class (see here – http://docs.oracle.com/javase/7/docs/api/java/sql/Statement.html): By default, only one ResultSet object per Statement object can be open at the same time. Therefore, if the reading of one ResultSet object is … Read more

MySQL Server on MAMP-Windows Will Not Start

I had the same problem. I contacted mamp support, and their answer was the following; it worked for me. Hope this helps you too. Stop all servers in MAMP. The below assumes your MAMP installation directory is C:\MAMP\. For MAMP: With Windows Explorer go to folder C:\MAMP\db\mysql\ First backup all files that begin with mysql-bin.*, then delete them … Read more

Create a temporary table in a SELECT statement without a separate CREATE TABLE

From the manual found at http://dev.mysql.com/doc/refman/5.7/en/create-table.html You can use the TEMPORARY keyword when creating a table. A TEMPORARY table is visible only to the current session, and is dropped automatically when the session is closed. This means that two different sessions can use the same temporary table name without conflicting with each other or with … Read more

How to install Python MySQLdb module using pip?

It’s easy to do, but hard to remember the correct spelling: If you need 1.2.x versions (legacy Python only), use pip install MySQL-python Note: Some dependencies might have to be in place when running the above command. Some hints on how to install these on various platforms: Ubuntu 14, Ubuntu 16, Debian 8.6 (jessie) Fedora … Read more

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