Section 6.4.1.6, “Windows Pluggable Authentication” 

## UNION 

Section 12.8.3, “Character Set and Collation of Function Results” Section 13.2.11.7, “Correlated Subqueries” Section 13.1.20, “CREATE TABLE Statement” Section 13.1.23, “CREATE VIEW Statement” Section 8.2.2.5, “Derived Condition Pushdown Optimization” Section 8.8.2, “EXPLAIN Output Format” Section 12.16, “Information Functions” Section 13.2.6.2, “INSERT ... ON DUPLICATE KEY UPDATE Statement” Section 8.4.4, “Internal Temporary Table Use in MySQL” Section 15.7.3, “Locks Set by Different SQL Statements in InnoDB” Section 11.1.6, “Numeric Type Attributes” Section 8.2.2.4, “Optimizing Derived Tables, View References, and Common Table Expressions with Merging or Materialization” Section 8.2.2.1, “Optimizing IN and EXISTS Subquery Predicates with Semijoin Transformations” Section 13.2.10.4, “Parenthesized Query Expressions” Section 8.2.1.2, “Range Optimization” Section 3.6.7, “Searching on Two Keys” Section 13.2.10.1, “SELECT ... INTO Statement” Section 13.2.10, “SELECT Statement” Section 5.1.10, “Server Status Variables” Section 13.2.11, “Subqueries” Section 13.2.12, “TABLE Statement” Section 16.7, “The MERGE Storage Engine” Section 13.2.10.3, “UNION Clause” Section 25.5.3, “Updatable and Insertable Views” Section 13.2.14, “VALUES Statement” Section 25.5.1, “View Syntax” Section 1.3, “What Is New in MySQL 8.0” Section 13.2.15, “WITH (Common Table Expressions)” Section 12.12, “XML Functions” 

## UNION ALL 

Section 12.16, “Information Functions” Section 8.4.4, “Internal Temporary Table Use in MySQL” Section 8.2.2.4, “Optimizing Derived Tables, View References, and Common Table Expressions with Merging or Materialization” Section 13.2.10.3, “UNION Clause” Section 25.5.3, “Updatable and Insertable Views” 

## UNION DISTINCT 

Section 13.2.10.3, “UNION Clause” Section 13.2.15, “WITH (Common Table Expressions)” 

## UNLOCK INSTANCE 

Section 1.3, “What Is New in MySQL 8.0” 

## UNLOCK TABLES 

Section 8.6.2, “Bulk Data Loading for MyISAM Tables” Section 7.2, “Database Backup Methods” Section 13.7.8.3, “FLUSH Statement” 

