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https://dev.mysql.com/doc/refman/8.4/en/statement-caching.html
Metadata changes occur for DDL statements such as those that create, drop, alter, rename, or truncate tables, or that analyze, optimize, or repair tables. For certain statements that a client might execute multiple times during a session, the ...
https://dev.mysql.com/doc/refman/8.4/en/statement-labels.html
[begin_label:] BEGIN [statement_list] END [end_label] [begin_label:] LOOP statement_list END LOOP [end_label] [begin_label:] REPEAT statement_list UNTIL search_condition END REPEAT [end_label] [begin_label:] WHILE search_condition DO statement_list ...
https://dev.mysql.com/doc/refman/8.4/en/static-format.html
Creating a table having such columns with an explicit ROW_FORMAT clause does not raise an error or warning; the format specification is ignored. It is used when the table contains no variable-length columns (VARCHAR, VARBINARY, BLOB, or TEXT). Of ...
https://dev.mysql.com/doc/refman/8.4/en/string-comparison-functions.html
For example, consider the following table and data: CREATE TABLE foo (bar VARCHAR(10)); INSERT INTO foo VALUES (NULL), (NULL); The query SELECT COUNT(*) FROM foo WHERE bar LIKE '%baz%'; returns 0. Table 14.13 String Comparison Functions and ...
https://dev.mysql.com/doc/refman/8.4/en/string-literals.html
A string is a sequence of bytes or characters, enclosed within either single quote (') or double quote (") characters. Examples: 'a string' "another string" Quoted strings placed next to each other are concatenated to a single string. The following ...
https://dev.mysql.com/doc/refman/8.4/en/telemetry-metrics-meters.html
For example, to update the frequency of the mysql.inno metrics: mysql>update performance_schema.setup_meters set FREQUENCY='30' where name = 'mysql.inno'; The maximum number of meter instruments which can be created is set by ...
https://dev.mysql.com/doc/refman/8.4/en/uninstall-plugin.html
If you are uninstalling a plugin with no intention of reinstalling it later and you care about the table contents, you should dump the table with mysqldump and remove the WITH PARSER clause from the dumped CREATE TABLE statement so that you can ...
https://dev.mysql.com/doc/refman/8.4/en/upgrade-prerequisites.html
Triggers must not have a missing or empty definer or an invalid creation context (indicated by the character_set_client, collation_connection, Database Collation attributes displayed by SHOW TRIGGERS or the INFORMATION_SCHEMA TRIGGERS table). To ...
https://dev.mysql.com/doc/refman/8.4/en/verifying-index-usage.html
Always check whether all your queries really use the indexes that you have created in the tables. Use the EXPLAIN statement, as described in Section 10.8.1, “Optimizing Queries with EXPLAIN”.
https://dev.mysql.com/doc/refman/8.4/en/while.html
Example: CREATE PROCEDURE dowhile() BEGIN DECLARE v1 INT DEFAULT 5; WHILE v1 > 0 DO ... [begin_label:] WHILE search_condition DO statement_list END WHILE [end_label] The statement list within a WHILE statement is repeated as long as the ...