Read this SQL tutorial to learn when to use SELECT, JOIN, subselects and UNION to access multiple tables with a single statement.

How to Build a Query String in T-SQL. Dynamic SQL lets you create a query string based off of user input. SQL Server allows you to create dynamic SQL statements.

How to Select a Subset in MySQL. The Structured Query Language, used in the MySQL database, has great flexibility for selecting subsets of data from database tables. SQL's SELECT statement shows ...