DICTIONARY tables are often large. Therefore, if you are looking for specific information, use a WHERE clause to retrieve a subset of the rows in a DICTIONARY table. In the following example, only the ...

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 join combines two or more tables side by side. If you do not specify how to join the tables, you get a Cartesian product. This means that SQL combines each row from the first table with every row ...

The information schema consists of a set of views that contain information about the objects defined in the current database. The information schema is defined in the SQL standard and can therefore be ...

SQL partitioning is a process of splitting a table into multiple subtables based on a predefined criterion, such as a column value, a range, a hash function, or a list.

Learn how to link tables based on a condition with inner join, left join, right join, and full join in SQL queries.

9 best practices for faster SQL queries Retrieve only the columns you need Use CASE instead of UPDATE for conditional column updates Keep large-table queries to a minimum Pre-stage your data ...

How to Reindex SQL Tables. The indexes on a the tables of a large database make a huge difference in its performance and utility. Without an index, locating a single record in a large table can ...

SQL lets you use one command to quickly create a new table containing a subset of records from a larger table while working in Access. Sound complicated? It's not, as Mary Ann Richardson shows us.