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https://dev.mysql.com/doc/refman/8.4/en/string-comparison-functions.html
If either expr or pat is NULL, the result is NULL. Note Aggregate queries involving NOT LIKE comparisons with columns containing NULL may yield unexpected results. For example, consider the following table and data: CREATE TABLE foo (bar ... Table ...
https://dev.mysql.com/doc/refman/8.4/en/trigger-syntax.html
To create a trigger or drop a trigger, use the CREATE TRIGGER or DROP TRIGGER statement, described in Section 15.1.22, “CREATE TRIGGER Statement”, and Section 15.1.34, “DROP TRIGGER Statement”. Here is a simple example that associates a ...
https://dev.mysql.com/doc/c-api/8.4/en/mysql-fetch-row.html
mysql_fetch_row() retrieves the next row of a result set: When used after mysql_store_result() or mysql_store_result_nonblocking(), mysql_fetch_row() returns NULL if there are no more rows to retrieve. When used after mysql_use_result(), ...
https://dev.mysql.com/doc/c-api/8.4/en/mysql-real-connect.html
The client attempts to connect as follows: If host is NULL or the string "localhost", a connection to the local host is assumed: On Windows, the client connects using a shared-memory connection, if the server has shared-memory connections enabled.
https://dev.mysql.com/doc/extending-mysql/8.4/en/plugin-status-system-variables.html
For example: static int my_foo; static MYSQL_SYSVAR_INT(foo_var, my_foo, PLUGIN_VAR_RQCMDARG, "foo comment", NULL, NULL, 0, 0, INT_MAX, 0); ... For example: static MYSQL_THDVAR_BOOL(some_flag, PLUGIN_VAR_NOCMDARG, "flag comment", NULL, NULL, FALSE); ... The server plugin interface enables plugins to expose status and system variables using the status_vars and system_vars members of the general plugin ...
https://dev.mysql.com/doc/heatwave/en/mys-hwgenai-hw-chat.html
Default value is NULL report_progress: specifies whether information such as routine progress detail is to be reported. The HEATWAVE_CHAT routine automatically calls the ML_RAG routine which loads an LLM and runs a semantic search on the available ...
https://dev.mysql.com/doc/refman/8.4/en/column-count-limit.html
mysql> CREATE TABLE t2 (c1 VARCHAR(65533) NOT NULL) ENGINE = InnoDB CHARACTER SET latin1; Query OK, 0 rows affected (0.01 sec) For MyISAM tables, NULL columns require additional space in the row to record whether their values are NULL. Each NULL ...
https://dev.mysql.com/doc/refman/8.4/en/hash-joins.html
row *************************** id: 1 select_type: SIMPLE table: t1 partitions: NULL type: ALL possible_keys: NULL key: NULL key_len: NULL ref: NULL rows: 1 filtered: 100.00 Extra: NULL *************************** 2. row *************************** ...It is possible to control whether hash joins are employed using one of the BNL and NO_BNL optimizer hints, or by setting block_nested_loop=on or block_nested_loop=off as part of the setting for the optimizer_switch server system ...
https://dev.mysql.com/doc/refman/8.4/en/invisible-indexes.html
row *************************** id: 1 select_type: SIMPLE table: t1 partitions: NULL type: range possible_keys: j_idx key: j_idx key_len: 5 ref: NULL rows: 2 filtered: 100.00 Extra: Using index condition mysql> EXPLAIN SELECT i, j FROM t1 WHERE j >= ... MySQL supports invisible indexes; that is, indexes that are not used by the ...
https://dev.mysql.com/doc/refman/8.4/en/keyring-functions-general-purpose.html
If the key cannot be created, the return value is NULL and an error occurs. mysql> SELECT @x; +------+ | @x | +------+ | NULL | +------+ mysql> SELECT keyring_key_generate('x', 'AES', 16) INTO @x; mysql> SELECT @x; +------+ | @x | +------+ | 1 | ...