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 ...

In most implementations of SQL, you pull information from two tables by using a SELECT command in this form: SELECT table1.column1, table1.column2, table2.column1, table2.column2 ...

How to Reindex SQL Tables. ... Microsoft's SQL Server has a handy command that rebuilds all indexes in a table. Oracle users typically rebuild each index in a table individually.