Posted by scf84 5 years ago In:

,

scf84
scf84 Asked:

What does the JOIN keyword do in SQL?

Liked this question? Tell your friends about it

Best Answer

yoavdothan
yoavdothan Answered:

A join combines records from two or more tables in a relational database. In the Structured Query Language (SQL), there are three types of joins: inner, outer, and cross. Outer joins are subdivided further into left outer joins, right outer joins, and full outer joins.

Mathematically, join is relation composition, the fundamental operation in relational algebra, and generalizing function composition.

see: http://en.wikipedia.org/wiki/JOIN

Add a comment Report

Related Questions

Other people asked questions on similar topics, check out the answers they received:

Pamela walker

Asked: What is DDL and DMl?

What is DDL and DMl?
agimoura

Asked: SQL

Can I use " $sql="select * from books where id='$idprod' limit 1"; or $sql3="select * from magazines where id='$idprod' limit 1"; " in order to use the same php file for both situations?
ss

Asked: How to use >all key word in sql queries

how to use >all key word in sql queries
  • Posted by ss 3 years ago