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https://dev.mysql.com/doc/refman/8.4/en/case.html
The CASE statement cannot have an ELSE NULL clause, and it is terminated with END CASE instead of END. This syntax cannot be used to test for equality with NULL because NULL = NULL is false. CASE case_value WHEN when_value THEN statement_list [WHEN ...
https://dev.mysql.com/doc/refman/8.4/en/change-replication-source-to.html
PRIVILEGE_CHECKS_USER = {NULL | 'account'} Names a user account that supplies a security context for the specified channel. NULL, which is the default, means no security context is used. When PRIVILEGE_CHECKS_USER is NULL (the default), the user ...
https://dev.mysql.com/doc/refman/8.4/en/date-and-time-type-syntax.html
Also, any TIMESTAMP not explicitly declared as NOT NULL permits NULL values. You can also set any TIMESTAMP column to the current date and time by assigning it a NULL value, unless it has been defined with the NULL attribute to permit NULL values.
https://dev.mysql.com/doc/refman/8.4/en/dynamic-format.html
NULL columns require additional space in the row to record whether their values are NULL. Each NULL column takes one bit extra, rounded up to the nearest byte. Dynamic storage format is used if a MyISAM table contains any variable-length columns ...
https://dev.mysql.com/doc/refman/8.4/en/events-privileges.html
To enable or disable the execution of scheduled events, it is necessary to set the value of the global event_scheduler system variable. The EVENT privilege governs the creation, modification, and deletion of events. For example, suppose that ...
https://dev.mysql.com/doc/refman/8.4/en/gis-format-conversion-functions.html
If the options argument is NULL, the return value is NULL. MySQL supports the functions listed in this section for converting geometry values from internal geometry format to WKT or WKB format, or for swapping the order of X and Y coordinates.
https://dev.mysql.com/doc/refman/8.4/en/gis-wkt-functions.html
If the options argument is NULL, the return value is NULL. These functions take as arguments a Well-Known Text (WKT) representation and, optionally, a spatial reference system identifier (SRID). For a description of WKT format, see Well-Known Text ...
https://dev.mysql.com/doc/refman/8.4/en/gtid-functions.html
timeout must be greater than or equal to 0; when running in strict SQL mode, a negative timeout value is immediately rejected with an error (ER_WRONG_ARGUMENTS); otherwise the function returns NULL, and raises a warning. The functions described in ...
https://dev.mysql.com/doc/refman/8.4/en/information-schema-innodb-metrics-table.html
row *************************** NAME: dml_inserts SUBSYSTEM: dml COUNT: 3 MAX_COUNT: 3 MIN_COUNT: NULL AVG_COUNT: 0.046153846153846156 COUNT_RESET: 3 MAX_COUNT_RESET: 3 MIN_COUNT_RESET: NULL AVG_COUNT_RESET: NULL TIME_ENABLED: 2014-12-04 14:18:28 ...
https://dev.mysql.com/doc/refman/8.4/en/information-schema-innodb-virtual-table.html
CREATE TABLE `t1` ( `a` int(11) DEFAULT NULL, `b` int(11) DEFAULT NULL, `c` int(11) GENERATED ALWAYS AS (5) VIRTUAL ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4; However, metadata for such a column does appear in the INNODB_COLUMNS table. The ...