https://dev.mysql.com/triggers-table.html
To see information about a table's triggers, you must have the TRIGGER privilege for the table. The TRIGGERS table has these columns: TRIGGER_CATALOG The name of the catalog to which the trigger belongs. TRIGGER_SCHEMA The name of the schema ...
https://dev.mysql.com/update.html
If you update a column that has been declared NOT NULL by setting to NULL, an error occurs if strict SQL mode is enabled; otherwise, the column is set to the implicit default value for the column data type and the warning count is incremented.
https://dev.mysql.com/writing-audit-plugins.html
This section describes how to write a server-side audit plugin, using the example plugin found in the plugin/audit_null directory of MySQL source distributions. The audit_null.c and audit_null_variables.h source files in that directory implement an ...Note Other examples of plugins that use the audit plugin API are the query rewrite plugin (see Section 5.6.4, “The Rewriter Query Rewrite Plugin”) and the Version Tokens plugin (see Section 5.6.6, “Version ...
https://dev.mysql.com/c-api-functions.html
In the descriptions here, a parameter or return value of NULL means NULL in the sense of the C programming language, not a MySQL NULL value. Unless specified otherwise, functions returning a pointer return a non-NULL value to indicate success or a ... This section describes C API functions other than those used for prepared statements, the asychronous interface, or the replication stream ...
https://dev.mysql.com/c-api-prepared-call-statements.html
The expected return information from the procedure therefore consists of multiple result sets and a final status: One result set from a SELECT that displays the initial parameter values: 10, NULL, 30. (The OUT parameter is assigned a value by the ...
https://dev.mysql.com/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/create-table-select.html
For example: mysql> CREATE TABLE test (a INT NOT NULL AUTO_INCREMENT, -> PRIMARY KEY (a), KEY(b)) -> ENGINE=MyISAM SELECT b,c FROM test2; This creates a MyISAM table with three columns, a, b, and c. Retrained attributes are NULL (or NOT NULL) and, ... You can create one table from another by adding a SELECT statement at the end of the CREATE TABLE statement: CREATE TABLE new_tbl [AS] SELECT * FROM orig_tbl; MySQL creates new columns for all elements in the ...
https://dev.mysql.com/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/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/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 ...
