The Best of the Week (May 9): SQL Zone

Make sure you didn't miss anything with this list of the Best of the Week in the SQL Zone (May 9 to May 15). Here they are, in order of popularity:

1. Myth: Select * Is Bad

This is one of the most persistent myths the author has seen in the field. It’s been there for decades. If a myth is alive that long, there must be some truth behind it. So, what could be bad about select *? Let’s have a closer look.

2. Results of the SQL Performance Quiz: 60% Fail

In 2011, the author launched “The 3-Minute Test: What do you know about SQL performance.” It consists of five questions that follow a simple pattern: each shows a query/index pair and asks if it demonstrates proper indexing or not. This article analyzes the 28,000 responses to spot patterns and make observations.

3. The Index You’ve Added is Useless. Why?

In this article, the author explores the fact that Oracle doesn't put NULL values in "ordinary" indexes, the problems this can cause, and how to get around them.

4. How to Import CSV Data into PostgreSQL

Many database servers support CSV data transfers, and this post will show one way you can import CSV files to PostgreSQL.

5. GTIDs in MySQL 5.6: New Replication Protocol, New Ways to Break Replication

Reconnecting a slave to a new master in MySQL 5.6 has always been a challenge, but it is so trivial when GTIDs are enabled. However, using GTIDs is not only about replacing good old binlog file/position with unique identifiers; it is also using a new replication protocol. And if you are not aware of it, it can bite.