Relational Operator - Join

Relational Algebra Between Sql And Query Plan

Relational Operator - Join

About

join is a relational operator that pair tuples (row) of two relations (table, …) according to a condition (predicate).

Notation

Relational

<MATH> \LARGE R_1 \bowtie_c R_2 </MATH> where:

SQL

See SQL - Joins (Home)

Symbol

Type Symbol Unicode Point Latex
Join <math>\Join</math> 2A1D \Join
Left Outer Join ⟕ 27D5 \leftouterjoin
Right Outer Join ⟖ 27D6 \rightouterjoin
Full Outer Join ⟗ 27D7 \fullouterjoin

Rule

<MATH> \LARGE R_1 \bowtie_{ predicate } R_2 = \sigma_{ predicate } ( R_1 \times R_2 ) </MATH> which means:

is the same than

Type

Logical

Short hand:

Implementation




Discover More
Card Puncher Data Processing
Calcite - Join

in Calcite. Join is a calcite relational operator (RelNode) Example field addressing in a join between the input EMP and DEPT The ordinal referencing is: 0=EMP 0=EMPNO, 1=ENAME, 2=JOB,...
Data System Architecture
Logical Data Modeling - Duplicate

A duplicate happens when in a set two elements have an equivalence relationship that returns true. In the set {1,1,2,3}, 1 is a duplicate The set {1,2,3} has no duplicate relational operators...
Relational Algebra Between Sql And Query Plan
Relation Operator - Nested Loop Join

Nested loop joins are join operator. They are useful when small subsets of data are being joined and if the join condition is an efficient way of accessing the second table. NESTED LOOPS is a row operation....
Relational Algebra Between Sql And Query Plan
Relational Algebra - Expression and Operators

Relational algebra is based upon the fact that you can pass tabular data through a set of data operators (select, filter, join, sort, union, etc.) in a algebraic structure. It means that: the output...
Venn Diagram
Relational Algebra - Intersect operator (intersection)

intersect (or intersection) is a relational operator that returns the intersection of two relation A and B, denoted by A ∩ B. An intersection is defined as all tuples (rows) that are present in both...
Theta Join
Relational Algebra - Theta-join

A theta-join is a difficult/complex join where the condition is not a equality. Example: Band join or range join. A theta is a join that links tables based on a relationship other than the equality...
Relational Algebra Between Sql And Query Plan
Relational Operator - Cross Product

The set cartesian product applied to a set of row (ie a tables) create all pairs of tuples (row). A cross-join (also called Cartesian join) occurs when a request does not have a join condition between...
Relational Algebra Between Sql And Query Plan
Relational Operator - Equi-joins

An Equi-join is a join where the condition (predicate) is an equality. theta join An equi-join links two relations (tables, ...) on common values in a column in relation 1 with a column in relation...
Relational Algebra Between Sql And Query Plan
Relational Operator - Hash Joins

Hash joins are join operation used for joining large data sets. The optimizer uses: the smaller of two tables or data sources or if the size is unknown the right-hand side to build a hash table...
Data System Architecture
SQL - Joins (Home)

in SQL. A join is a SQL clause statement which define the set operation such as: intersection, union, that the database must perform between two or more relation (table, view, query, ...). The...



Share this page:
Follow us:
Task Runner