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Each row in this table corresponds to an individual partition or subpartition of a partitioned table. The PARTITIONS table has these columns: TABLE_CATALOG The name of the catalog to which the table belongs. TABLE_SCHEMA The name of the schema ...
InnoDB tables are created using the CREATE TABLE statement; for example: CREATE TABLE t1 (a INT, b CHAR (20), PRIMARY KEY (a)) ENGINE=InnoDB; The ENGINE=InnoDB clause is not required when InnoDB is defined as the default storage engine, which it is ...For information about row format characteristics, see Section 14.11, “InnoDB Row ...
This section describes how to rebuild or repair tables or indexes, which may be necessitated by: Changes to how MySQL handles data types or character sets. For example, an error in a collation might have been corrected, necessitating a table ...
There are different reasons for creating InnoDB tables externally; that is, creating tables outside of the data directory. Those reasons might include space management, I/O optimization, or placing tables on a storage device with particular ...An ...
The table stores one row per thread showing the current status of the thread's most recent monitored wait event, so there is no system variable for configuring the table size. Of the tables that contain wait event rows, events_waits_current is the ...The THREAD_ID and EVENT_ID values taken together uniquely identify the ...
The effective maximum table size for MySQL databases is usually determined by operating system constraints on file sizes, not by MySQL internal limits. Windows users, please note that FAT and VFAT (FAT32) are not considered suitable for production ...For up-to-date information operating system file size limits, refer to the documentation specific to your operating ...
You can create one table from another by adding a SELECT statement at the end of the CREATE TABLE statement: CREATE TABLE new_tbl [AS] SELECT * FROM orig_tbl; MySQL creates new columns for all elements in the SELECT. For example: mysql> CREATE ...
The optimizer handles derived tables and view references the same way: It avoids unnecessary materialization whenever possible, which enables pushing down conditions from the outer query to derived tables and produces more efficient execution plans.
A derived table is an expression that generates a table within the scope of a query FROM clause. For example, a subquery in a SELECT statement FROM clause is a derived table: SELECT ... The [AS] tbl_name clause is mandatory because every table in a ...This does not work: SELECT AVG(SUM(column1)) FROM t1 GROUP BY column1; However, this query provides the desired information: SELECT AVG(sum_column1) FROM (SELECT SUM(column1) AS sum_column1 FROM t1 GROUP BY column1) AS t1; Notice that the column name used within the subquery (sum_column1) is recognized in the outer ...
The Performance Schema maintains tables for collecting current and recent statement events, and aggregates that information in summary tables. Section 25.12.6, “Performance Schema Statement Event Tables” describes the events on which statement ...Example statement event summary information: mysql> SELECT * FROM performance_schema.events_statements_summary_global_by_event_name\G *************************** ...