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https://dev.mysql.com/doc/refman/8.4/en/example-maximum-row.html
Task: Find the number, dealer, and price of the most expensive article.
https://dev.mysql.com/doc/refman/8.4/en/exists-and-not-exists-subqueries.html
For the preceding example, if t2 contains any rows, even rows with nothing but NULL values, the EXISTS condition is TRUE. If a subquery returns any rows at all, EXISTS subquery is TRUE, and NOT EXISTS subquery is FALSE. For example: SELECT column1 ...
https://dev.mysql.com/doc/refman/8.4/en/function-optimization.html
A function is nondeterministic if, given fixed values for its arguments, it can return different results for different invocations. If a function is tagged nondeterministic, a reference to it in a WHERE clause is evaluated for every row (when ...
https://dev.mysql.com/doc/refman/8.4/en/group-replication-launching.html
It should show something like this: mysql> SHOW PLUGINS; +----------------------------+----------+--------------------+----------------------+-------------+ | Name | Status | Type | Library | License | ... It is first necessary to ensure that the ...
https://dev.mysql.com/doc/refman/8.4/en/group-replication-requirements.html
Every table that is to be replicated by the group must have a defined primary key, or primary key equivalent where the equivalent is a non-null unique key. Infrastructure Server Instance Configuration Server instances that you want to use for Group ...
https://dev.mysql.com/doc/refman/8.4/en/information-schema-plugins-table.html
If the library name is NULL, the plugin is compiled in and cannot be uninstalled with UNINSTALL PLUGIN. The PLUGINS table has these columns: PLUGIN_NAME The name used to refer to the plugin in statements such as INSTALL PLUGIN and UNINSTALL PLUGIN.
https://dev.mysql.com/doc/refman/8.4/en/information-schema-schemata-table.html
A schema is a database, so the SCHEMATA table provides information about databases. The SCHEMATA table has these columns: CATALOG_NAME The name of the catalog to which the schema belongs. The following statements are equivalent: SELECT SCHEMA_NAME ...
https://dev.mysql.com/doc/refman/8.4/en/innodb-online-ddl-failure-conditions.html
For example, you might insert duplicate values into a column while a unique index is being created, or you might insert NULL values into a column while creating a primary key index on that column. The failure of an online DDL operation is typically ...
https://dev.mysql.com/doc/refman/8.4/en/innodb-online-ddl-limitations.html
The ALTER TABLE clause LOCK=NONE is not permitted if there are ON...CASCADE or ON...SET NULL constraints on the table. The following limitations apply to online DDL operations: The table is copied when creating an index on a TEMPORARY TABLE. Before ...
https://dev.mysql.com/doc/refman/8.4/en/innodb-online-ddl-single-multi.html
Before the introduction of online DDL, it was common practice to combine many DDL operations into a single ALTER TABLE statement. Because each ALTER TABLE statement involved copying and rebuilding the table, it was more efficient to make several ...