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https://dev.mysql.com/doc/refman/8.4/en/help.html
HELP 'search_string' The HELP statement returns online information from the MySQL Reference Manual. Its proper operation requires that the help tables in the mysql database be initialized with help topic information (see Section 7.1.17, ...
https://dev.mysql.com/doc/refman/8.4/en/if.html
[ELSE statement_list] END IF The IF statement for stored programs implements a basic conditional construct. Note There is also an IF() function, which differs from the IF statement described here. The IF statement can have THEN, ELSE, and ELSEIF ...
https://dev.mysql.com/doc/refman/8.4/en/information-schema-innodb-virtual-table.html
CREATE TABLE `t1` ( `a` int(11) DEFAULT NULL, `b` int(11) DEFAULT NULL, `c` int(11) GENERATED ALWAYS AS (5) VIRTUAL ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4; However, metadata for such a column does appear in the INNODB_COLUMNS table. The ...
https://dev.mysql.com/doc/refman/8.4/en/information-schema-key-column-usage-table.html
This table provides no information about functional key parts because they are expressions and the table provides information only about columns. The KEY_COLUMN_USAGE table has these columns: CONSTRAINT_CATALOG The name of the catalog to which the ...
https://dev.mysql.com/doc/refman/8.4/en/innodb-information-schema-metrics-table.html
Create a simple InnoDB table: mysql> USE test; Database changed mysql> CREATE TABLE t1 (c1 INT) ENGINE=INNODB; Query OK, 0 rows affected (0.02 sec) Enable the dml_inserts counter. The INNODB_METRICS table provides information about InnoDB ...
https://dev.mysql.com/doc/refman/8.4/en/innodb-online-ddl-failure-conditions.html
The tmpdir or innodb_tmpdir file system runs out of disk space, while MySQL writes temporary sort files on disk during index creation. For example, you might insert duplicate values into a column while a unique index is being created, or you might ... The failure of an online DDL operation is typically due to one of the following conditions: An ALGORITHM clause specifies an algorithm that is not compatible with the particular type of DDL operation or storage ...
https://dev.mysql.com/doc/refman/8.4/en/innodb-restrictions-limitations.html
You cannot create a table with a column name that matches the name of an internal InnoDB column (including DB_ROW_ID, DB_TRX_ID, and DB_ROLL_PTR. mysql> CREATE TABLE t1 (c1 INT, db_row_id INT) ENGINE=INNODB; ERROR 1166 (42000): Incorrect column name ... This section describes restrictions and limitations of the InnoDB storage ...
https://dev.mysql.com/doc/refman/8.4/en/insert-on-duplicate.html
If you specify an ON DUPLICATE KEY UPDATE clause and a row to be inserted would cause a duplicate value in a UNIQUE index or PRIMARY KEY, an UPDATE of the old row occurs. If column b is also unique, the INSERT is equivalent to this UPDATE statement ...
https://dev.mysql.com/doc/refman/8.4/en/insert-select.html
When selecting from and inserting into the same table, MySQL creates an internal temporary table to hold the rows from the SELECT and then inserts those rows into the target table. To ensure that the binary log can be used to re-create the original ... INSERT [LOW_PRIORITY | HIGH_PRIORITY] [IGNORE] [INTO] tbl_name [PARTITION (partition_name [, partition_name] ...)] [(col_name [, col_name] ...)] { SELECT ...
https://dev.mysql.com/doc/refman/8.4/en/insert.html
If both the column list and the VALUES list are empty, INSERT creates a row with each column set to its default value: INSERT INTO tbl_name () VALUES(); If strict mode is not enabled, MySQL uses the implicit default value for any column that has no ... INSERT [LOW_PRIORITY | DELAYED | HIGH_PRIORITY] [IGNORE] [INTO] tbl_name [PARTITION (partition_name [, partition_name] ...)] [(col_name [, col_name] ...)] { {VALUES | VALUE} (value_list) [, (value_list)] ...