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https://dev.mysql.com/doc/refman/5.7/en/create-table-select.html
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 ...
https://dev.mysql.com/doc/refman/5.7/en/derived-table-optimization.html
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.
https://dev.mysql.com/doc/refman/5.7/en/derived-tables.html
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 ...
https://dev.mysql.com/doc/refman/5.7/en/performance-schema-statement-summary-tables.html
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 *************************** ...
https://dev.mysql.com/doc/refman/5.7/en/truncate-table.html
Logically, TRUNCATE TABLE is similar to a DELETE statement that deletes all rows, or a sequence of DROP TABLE and CREATE TABLE statements. Thus, it cannot be rolled back, it does not cause ON DELETE triggers to fire, and it cannot be performed for ...To achieve high performance, it bypasses the DML method of deleting ...
https://dev.mysql.com/doc/refman/5.7/en/information-schema-innodb-temp-table-info-table.html
The INNODB_TEMP_TABLE_INFO table provides information about user-created InnoDB temporary tables that are active in an InnoDB instance. It does not provide information about internal InnoDB temporary tables used by the optimizer. The ...The number ...
https://dev.mysql.com/doc/refman/5.7/en/multiple-tables.html
The pet table keeps track of which pets you have. If you want to record other information about them, such as events in their lives like visits to the vet or when litters are born, you need another table. What should this table look like? It needs ...An event type field, if you want to be able to categorize ...
https://dev.mysql.com/doc/refman/5.7/en/innodb-information-schema-temp-table-info.html
INNODB_TEMP_TABLE_INFO provides information about user-created InnoDB temporary tables that are active in the InnoDB instance. It does not provide information about internal InnoDB temporary tables used by the optimizer. mysql> SHOW TABLES FROM ...
https://dev.mysql.com/doc/refman/5.7/en/mysql-cluster-disk-data-objects.html
For example, if an NDB Cluster has 4 data nodes, then the ALTER TABLESPACE statement just shown creates 4 data files, 1 each in the data directory of each of the 4 data nodes; each of these files is named data_2.dat and each file is 48 MB in size.
https://dev.mysql.com/doc/refman/5.7/en/mysql-cluster-install-example-data.html
To specify this, use the ENGINE=NDBCLUSTER or ENGINE=NDB option when creating the table: CREATE TABLE tbl_name (col_name column_definitions) ENGINE=NDBCLUSTER; Alternatively, for an existing table that uses a different storage engine, use ALTER ...