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https://dev.mysql.com/doc/refman/8.4/en/dynamic-system-variables.html
Many server system variables are dynamic and can be set at runtime. For a description of the privilege requirements for setting system variables, see Section 7.1.9.1, “System Variable Privileges” The following table lists all dynamic system ...
https://dev.mysql.com/doc/refman/8.4/en/engine-condition-pushdown-optimization.html
This optimization improves the efficiency of direct comparisons between a nonindexed column and a constant. In such cases, the condition is “pushed down” to the storage engine for evaluation. This optimization can be used only by the NDB ...
https://dev.mysql.com/doc/refman/8.4/en/example-auto-increment.html
You can also explicitly assign 0 to the column to generate sequence numbers, unless the NO_AUTO_VALUE_ON_ZERO SQL mode is enabled. For example: INSERT INTO animals (id,name) VALUES(0,'groundhog'); If the column is declared NOT NULL, it is also ...
https://dev.mysql.com/doc/refman/8.4/en/extensions-to-ansi.html
MySQL Server supports some extensions that you are not likely to find in other SQL DBMSs. Be warned that if you use them, your code is most likely not portable to other SQL servers. For example, MySQL Server recognizes the STRAIGHT_JOIN keyword in ...
https://dev.mysql.com/doc/refman/8.4/en/flow-control-functions.html
The second syntax returns the result for the first condition that is true. If no comparison or condition is true, the result after ELSE is returned, or NULL if there is no ELSE part. Note The syntax of the CASE operator described here differs ...
https://dev.mysql.com/doc/refman/8.4/en/information-schema-table-constraints-table.html
The TABLE_CONSTRAINTS table has these columns: CONSTRAINT_CATALOG The name of the catalog to which the constraint belongs. CONSTRAINT_SCHEMA The name of the schema (database) to which the constraint belongs. TABLE_SCHEMA The name of the schema ...
https://dev.mysql.com/doc/refman/8.4/en/innodb-page-compression.html
InnoDB supports page-level compression for tables that reside in file-per-table tablespaces. Page compression is enabled by specifying the COMPRESSION attribute with CREATE TABLE or ALTER TABLE. Supported Platforms Page compression requires sparse ...
https://dev.mysql.com/doc/refman/8.4/en/json-attribute-functions.html
The functions in this section return attributes of JSON values. An error occurs if the argument is not a valid JSON document. An empty array, empty object, or scalar value has depth 1. A nonempty array containing only elements of depth 1 or ...
https://dev.mysql.com/doc/refman/8.4/en/keywords.html
Certain keywords, such as SELECT, DELETE, or BIGINT, are reserved and require special treatment for use as identifiers such as table and column names. This may also be true for the names of built-in functions. Some keywords which are otherwise ...
https://dev.mysql.com/doc/refman/8.4/en/locking-service.html
MySQL distributions provide a locking interface that is accessible at two levels: At the SQL level, as a set of loadable functions that each map onto calls to the service routines. As a C language interface, callable as a plugin service from server ...