SQL: Difference between revisions

From NovaOrdis Knowledge Base
Jump to navigation Jump to search
No edit summary
Line 9: Line 9:
=Overview=
=Overview=
This article documents standard SQL. For database-specific extensions, we'll link to the databases-specific DML operations page.
This article documents standard SQL. For database-specific extensions, we'll link to the databases-specific DML operations page.
=TO DEPLETE=
<font color=darkkhaki>
=<tt>SELECT</tt>=
==<tt>JOIN</tt> Clause==
A <code>SELECT</code> <code>JOIN</code> clause is using to query and access rows from two or more tables by establishing a logical relationship between those rows. The relationship is based on common field values, specified in the <code>JOIN</code> clause with the keyword <code>ON</code>.
==<tt>WHERE</tt> Clause==
=JOIN=
The SQL <code>JOIN</code> clause is used to combine rows from two or more tables, based on a related column between them.
==INNER JOIN==
Return records that have matching values in both tables.
==LEFT (OUTER) JOIN==
Return all records from the left table and the matching records from the right table.
==RIGHT (OUTER) JOIN==
Return all records from the right table and the matching records from the left table.
==FULL (OUTER) JOIN==
Returns all records when there is a match in either left or right table.

Revision as of 20:37, 22 May 2024

External

Internal

Overview

This article documents standard SQL. For database-specific extensions, we'll link to the databases-specific DML operations page.