https://dev.mysql.com/select.html
This exception may not apply to const or system tables that are used on the NULL-complemented side of an outer join (that is, the right-side table of a LEFT JOIN or the left-side table of a RIGHT JOIN. SELECT [ALL | DISTINCT | DISTINCTROW ] ...
https://dev.mysql.com/show-create-procedure.html
The value displayed for the Create Procedure or Create Function field is NULL if you have only CREATE ROUTINE, ALTER ROUTINE, or EXECUTE. SHOW CREATE PROCEDURE proc_name This statement is a MySQL extension. It returns the exact string that can be ...
https://dev.mysql.com/show-profile.html
For values that depend on the getrusage() system call, NULL is returned on systems such as Windows that do not support the call. Note The SHOW PROFILE and SHOW PROFILES statements are deprecated and will be removed in a future MySQL release. Use the ...
https://dev.mysql.com/signal.html
It is illegal to assign NULL to a condition information item in a SIGNAL statement. SIGNAL provides error information to a handler, to an outer portion of the application, or to the client. Also, it provides control over the error's characteristics ...
https://dev.mysql.com/silent-column-changes.html
Columns that are part of a PRIMARY KEY are made NOT NULL even if not declared that way. In some cases, MySQL silently changes column specifications from those given in a CREATE TABLE or ALTER TABLE statement. These might be changes to a data type, ...
https://dev.mysql.com/spatial-index-optimization.html
MySQL permits creation of SPATIAL indexes on NOT NULL geometry-valued columns (see Section 11.4.10, “Creating Spatial Indexes”). The optimizer checks the SRID attribute for indexed columns to determine which spatial reference system (SRS) to ...
https://dev.mysql.com/sql-prepared-statements.html
Using prepared statements with placeholders for parameter values has the following benefits: Less overhead for parsing the statement each time it is executed. Typically, database applications process large volumes of almost-identical statements, ...
https://dev.mysql.com/start-slave.html
Cannot be set to an empty or null string, or left unset if PASSWORD is used. START SLAVE [thread_types] [until_option] [connection_options] [channel_option] thread_types: [thread_type [, thread_type] ... ] thread_type: IO_THREAD | SQL_THREAD ...
https://dev.mysql.com/subquery-materialization.html
oe [NOT] IN (SELECT ie ...) The predicate is IN or NOT IN and a result of UNKNOWN (NULL) has the same meaning as a result of FALSE. The optimizer uses materialization to enable more efficient subquery processing. Materialization speeds up query ...
https://dev.mysql.com/sys-host-summary-by-file-io-type.html
Rows for which the HOST column in the underlying Performance Schema table is NULL are assumed to be for background threads and are reported with a host name of background. These views summarize file I/O, grouped by host and event type. By default, ...
