JOIN Types Index

ALL

Section 7.13.6, “Nested-Loop Join Algorithms”

const

Section 7.8.2, “EXPLAIN Output Format”
Section 7.13.9, “ORDER BY Optimization”
Section 12.2.9, “SELECT Syntax”
Section 7.13.1.1, “The Range Access Method for Single-Part Indexes”

eq_ref

Section 7.8.2, “EXPLAIN Output Format”
Section 13.10.1, “MERGE Table Advantages and Disadvantages”
Section 7.13.12, “Optimizing IN/=ANY Subqueries”

fulltext

Section 7.8.2, “EXPLAIN Output Format”

index

Section 7.8.2, “EXPLAIN Output Format”
Section 7.13.6, “Nested-Loop Join Algorithms”

index_merge

Section 7.8.2, “EXPLAIN Output Format”
Section 7.13.2, “Index Merge Optimization”

index_subquery

Section 7.8.2, “EXPLAIN Output Format”
Section 7.13.12, “Optimizing IN/=ANY Subqueries”
Section 12.2.10.10, “Optimizing Subqueries”

range

Section 7.8.2, “EXPLAIN Output Format”
Section 7.13.2, “Index Merge Optimization”
Section 7.13.10.1, “Loose Index Scan”
Section 7.13.6, “Nested-Loop Join Algorithms”
Section 7.13.1, “Range Optimization”
Section 7.13.1.1, “The Range Access Method for Single-Part Indexes”

ref

Section 7.8.2, “EXPLAIN Output Format”
Section 13.10.1, “MERGE Table Advantages and Disadvantages”
Section 7.6.2, “MyISAM Index Statistics Collection”
Section 7.13.12, “Optimizing IN/=ANY Subqueries”

ref_or_null

Section 7.8.2, “EXPLAIN Output Format”
Section 7.13.4, “IS NULL Optimization”
Section 7.13.12, “Optimizing IN/=ANY Subqueries”

system

Section 7.8.2, “EXPLAIN Output Format”
Section 12.2.9, “SELECT Syntax”
Section 7.13.1.1, “The Range Access Method for Single-Part Indexes”

unique_subquery

Section 7.8.2, “EXPLAIN Output Format”
Section 7.13.12, “Optimizing IN/=ANY Subqueries”
Section 12.2.10.10, “Optimizing Subqueries”