https://dev.mysql.com/row-constructor-optimization.html
row *************************** id: 1 select_type: SIMPLE table: t1 partitions: NULL type: ref possible_keys: PRIMARY key: PRIMARY key_len: 4 ref: const rows: 3 filtered: 100.00 Extra: Using where In such cases, rewriting the row constructor ...For ...
https://dev.mysql.com/set.html
For example, a column specified as SET('one', 'two') NOT NULL can have any of these values: '' 'one' 'two' 'one,two' A SET column can have a maximum of 64 distinct members. A SET is a string object that can have zero or more values, each of which ...
https://dev.mysql.com/spatial-geohash-functions.html
Unless otherwise specified, functions in this section handle their arguments as follows: If any argument is NULL, the return value is NULL. Geohash is a system for encoding latitude and longitude coordinates of arbitrary precision into a text ...
https://dev.mysql.com/string-type-syntax.html
CHAR(0) is also quite nice when you need a column that can take only two values: A column that is defined as CHAR(0) NULL occupies only one bit and can take only the values NULL and '' (the empty string). A string object that can have only one ...
https://dev.mysql.com/sys-innodb-lock-waits.html
locked_table_partition The name of the locked partition, if any; NULL otherwise. locked_table_subpartition The name of the locked subpartition, if any; NULL otherwise. This field reports NULL if the session that issued the blocking query becomes ...
https://dev.mysql.com/sys-ps-is-consumer-enabled.html
Returns YES or NO to indicate whether a given Performance Schema consumer is enabled, or NULL if the argument is NULL. (Prior to MySQL 8.0.18, the function returns NULL if the argument is not a valid consumer name.) This function accounts for the ...If the argument is not a valid consumer name, an error ...
https://dev.mysql.com/where-optimization.html
This is also done for any NOT NULL expression when used with only one table. A table that is used with a WHERE clause on a PRIMARY KEY or a UNIQUE index, where all index parts are compared to constant expressions and are defined as NOT NULL. This ...
https://dev.mysql.com/writing-daemon-plugins.html
A daemon plugin is a simple type of plugin used for code that should be run by the server but that does not communicate with it. This section describes how to write a daemon server plugin, using the example plugin found in the plugin/daemon_example ...
https://dev.mysql.com/writing-keyring-plugins.html
The general descriptor also refers to keyring_system_variables, a structure that exposes a system variable to the SHOW VARIABLES statement: static struct st_mysql_sys_var *keyring_system_variables[]= { MYSQL_SYSVAR(data), NULL }; The keyring_init ...
https://dev.mysql.com/writing-password-validation-plugins.html
This section describes how to write a server-side password-validation plugin. The instructions are based on the source code in the plugin/password_validation directory of MySQL source distributions. The validate_password.cc source file in that ...
