You often need data that are stored in separate tables. For example, you may want to produce a report that gets information about flight delays from one table and boarding capacity from another.

If your eyes glazed over at the recent announcement of an “SQL injection” vulnerability in WordPress, take heart. You’re not alone. SQL injection attacks are a common kind of security flaw, but are ...

Read this SQL tutorial to learn when to use SELECT, JOIN, subselects and UNION to access multiple tables with a single statement. It’s sometimes difficult to know which SQL syntax to use when ...

A common SQL habit is to use SELECT * on a query, because it’s tedious to list all the columns you need. Plus, sometimes those columns may change over time, so why not just do things the easy way? But ...

Ok. I have some tables that store dollar amounts, among other data. I had the fields set to be a data type of money, and was planning on the values including zero. When selecting the data, I was ...