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https://dev.mysql.com/doc/refman/8.4/en/insert-on-duplicate.html
If you specify an ON DUPLICATE KEY UPDATE clause and a row to be inserted would cause a duplicate value in a UNIQUE index or PRIMARY KEY, an UPDATE of the old row occurs. If column b is also unique, the INSERT is equivalent to this UPDATE statement ...
https://dev.mysql.com/doc/refman/8.4/en/where-optimization.html
This section discusses optimizations that can be made for processing WHERE clauses. The examples use SELECT statements, but the same optimizations apply for WHERE clauses in DELETE and UPDATE statements. Note Because work on the MySQL optimizer is ...
https://dev.mysql.com/doc/mysql-monitor/8.0/en/group-management.html
For example, you can create groups for development and production instances. Instances added to each group inherit the Advisors scheduled for that group. There are two types of group in MySQL Enterprise Monitor: user-defined and replication.
https://dev.mysql.com/doc/mysql-monitor/8.0/en/mem-ui-backup-dashboard-overview.html
The following topics are described: Overview Filter Common Backup Status Information Backup Overview Backup History Common Backup Status Information This section describes the types of information reported on each backup. Backup Events: displays a ...
https://dev.mysql.com/doc/refman/8.4/en/entering-queries.html
Make sure that you are connected to the server, as discussed in the previous section. Doing so does not in itself select any database to work with, but that is okay. At this point, it is more important to find out a little about how to issue ...
https://dev.mysql.com/doc/refman/8.4/en/exists-and-not-exists-subqueries.html
If a subquery returns any rows at all, EXISTS subquery is TRUE, and NOT EXISTS subquery is FALSE. For example: SELECT column1 FROM t1 WHERE EXISTS (SELECT * FROM t2); Traditionally, an EXISTS subquery starts with SELECT *, but it could begin with ...
https://dev.mysql.com/doc/refman/8.4/en/hash-joins.html
It is possible to control whether hash joins are employed using one of the BNL and NO_BNL optimizer hints, or by setting block_nested_loop=on or block_nested_loop=off as part of the setting for the optimizer_switch server system variable. row ...
https://dev.mysql.com/doc/refman/8.4/en/load-xml.html
The tagname in the optional ROWS IDENTIFIED BY clause must also be given as a literal string, and must be surrounded by angle brackets (< and >). LOAD XML acts as the complement of running the mysql client in XML output mode (that is, starting the ...
https://dev.mysql.com/doc/refman/8.4/en/mysql-cluster-replication-conflict-resolution.html
Requirements Source Column Control Conflict Resolution Control Conflict Resolution Functions Conflict Resolution Exceptions Table Conflict Detection Status Variables Examples When using a replication setup involving multiple sources (including ...
https://dev.mysql.com/doc/refman/8.4/en/replication-gtids-functions.html
This section provides examples of stored functions (see Chapter 27, Stored Objects) which you can create using some of the built-in functions provided by MySQL for use with GTID-based replication, listed here: GTID_SUBSET(): Shows whether one GTID ...