https://dev.mysql.com/mysql-store-result-nonblocking.html
The two functions differ as follows: mysql_store_result() returns a pointer to a MYSQL_RESULT value that contains the result set, or NULL if there is no result set or an error occurred. When the return status is NET_ASYNC_COMPLETE, the result ...
https://dev.mysql.com/numeric-type-syntax.html
SERIAL is an alias for BIGINT UNSIGNED NOT NULL AUTO_INCREMENT UNIQUE. SERIAL DEFAULT VALUE in the definition of an integer column is an alias for NOT NULL AUTO_INCREMENT UNIQUE. SERIAL is an alias for BIGINT UNSIGNED NOT NULL AUTO_INCREMENT UNIQUE.
https://dev.mysql.com/optimizing-innodb-queries.html
If an indexed column cannot contain any NULL values, declare it as NOT NULL when you create the table. The optimizer can better determine which index is most effective to use for a query, when it knows whether each column contains NULL values. To ...
https://dev.mysql.com/parameters-table.html
The PARAMETER_NAME and PARAMETER_MODE values are NULL because the return value has no name and the mode does not apply. The PARAMETERS table provides information about parameters for stored routines (stored procedures and stored functions), and ...
https://dev.mysql.com/partitioning-linear-hash.html
MySQL also supports linear hashing, which differs from regular hashing in that linear hashing utilizes a linear powers-of-two algorithm whereas regular hashing employs the modulus of the hashing function's value. We call this value V; it can be ...
https://dev.mysql.com/partitioning-overview.html
This section provides a conceptual overview of partitioning in MySQL 8.0. For information on partitioning restrictions and feature limitations, see Section 23.6, “Restrictions and Limitations on Partitioning”. The SQL standard does not provide ...
https://dev.mysql.com/performance-schema-replication-tables.html
At this time, there are no active slave threads, so the THREAD_ID columns are NULL and the SERVICE_STATE columns have a value of OFF. After STOP SLAVE, the THREAD_ID columns become NULL and the SERVICE_STATE columns for threads that no longer exist ...This is similar to the information available from the SHOW SLAVE STATUS statement, but representation in table form is more accessible and has usability benefits: SHOW SLAVE STATUS output is useful for visual inspection, but not so much for programmatic ...
https://dev.mysql.com/performance-schema-system-variables.html
If an error occurs that is not instrumented, information for the occurrence is aggregated to the NULL row in each summary table; that is, to the row with ERROR_NUMBER=0, ERROR_NAME=NULL, and SQLSTATE=NULL. The Performance Schema automatically sizes ...
https://dev.mysql.com/prepared-statements-instances-table.html
OWNER_OBJECT_TYPE, OWNER_OBJECT_SCHEMA, OWNER_OBJECT_NAME For a prepared statement created by a client session, these columns are NULL. These columns can be used to find stored programs that leak prepared statements: SELECT OWNER_OBJECT_TYPE, ...
https://dev.mysql.com/processlist-table.html
For the SHOW PROCESSLIST statement, the value of STATE is NULL. INFO The statement the thread is executing, or NULL if it is not executing any statement. The PROCESSLIST table provides information about which threads are running. This is the same ...
