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 ...

I am trying to join two databases in an SQL query. Database A has a table with a 5 digit client number and another table with a 5 digit matter number. The other database, B, has a table with one field ...

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.

Now that you understand the basic structure of a SQL application, let's dissect the basis of information retrieval: the query. For many techies, especially those that focus on systems administration, ...

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 ...