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https://dev.mysql.com/doc/refman/8.4/en/string-comparison-functions.html
Note Aggregate queries involving NOT LIKE comparisons with columns containing NULL may yield unexpected results. The same is true for aggregate queries involving NULL and comparisons using NOT RLIKE or NOT REGEXP. Table 14.13 String Comparison ...
https://dev.mysql.com/doc/refman/8.4/en/subqueries.html
We say that the subquery is nested within the outer query, and in fact it is possible to nest subqueries within other subqueries, to a considerable depth. The main advantages of subqueries are: They allow queries that are structured so that it is ...
https://dev.mysql.com/doc/refman/8.4/en/subquery-restrictions.html
MySQL does not support LIMIT in subqueries for certain subquery operators: mysql> SELECT * FROM t1 WHERE s1 IN (SELECT s2 FROM t2 ORDER BY s1 LIMIT 1); ERROR 1235 (42000): This version of MySQL doesn't yet support 'LIMIT & IN/ALL/ANY/SOME subquery' ... In general, you cannot modify a table and select from the same table in a ...
https://dev.mysql.com/doc/refman/8.4/en/telemetry-metrics-meter-metrics.html
opened_tables Opened_tables ASYNC COUNTER The number of tables that have been opened prepared_stmt_count Prepared_stmt_count ASYNC GAUGE COUNTER The current number of prepared statements queries Queries ASYNC COUNTER The number of statements ... The ...
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/mysql-enterprise-backup/8.4/en/mysqlbackup.incremental.html
In order to that, after making first a full backup that contains all data, you can do one of the following: Performing a series of differential backups. Each differential backups includes all the changes made to the data since the last full backup ...
https://dev.mysql.com/doc/c-api/8.4/en/c-api-asynchronous-interface-usage.html
This section describes how to use the C API asynchronous interface. In this discussion, asynchronous and nonblocking are used as synonyms, as are synchronous and blocking. The asynchronous C API functions cover operations that might otherwise block ...
https://dev.mysql.com/doc/c-api/8.4/en/c-api-basic-interface-usage.html
For SELECT queries, you retrieve the selected rows as a result set. Application programs should use this general outline for interacting with MySQL by means of the client library: Initialize the MySQL client library by calling mysql_library_init().
https://dev.mysql.com/doc/c-api/8.4/en/mysql-affected-rows.html
uint64_t mysql_affected_rows(MYSQL *mysql) Description mysql_affected_rows() may be called immediately after executing a statement with mysql_real_query() or mysql_query(). It returns the number of rows changed, deleted, or inserted by the last ...
https://dev.mysql.com/doc/c-api/8.4/en/mysql-field-count.html
unsigned int mysql_field_count(MYSQL *mysql) Description Returns the number of columns for the most recent query on the connection. The normal use of this function is when mysql_store_result() returned NULL (and thus you have no result set pointer). In this case, you can call mysql_field_count() to determine whether mysql_store_result() should have produced a nonempty ...