MySQL :: MySQL 8.0 Reference Manual

Search Results

Displaying 221 to 226 of 226 total results

« Previous
21
22
23
Next »

10.2.2 Optimizing Subqueries, Derived Tables, View References, and Common Table Expressions

https://dev.mysql.com/doc/refman/8.0/en/subquery-optimization.html

Note A limitation on UPDATE and DELETE statements that use a subquery to modify a single table is that the optimizer does not use semijoin or materialization subquery optimizations. As a workaround, try rewriting them as multiple-table UPDATE and ...

30.4.5.1 The extract_schema_from_file_name() Function

https://dev.mysql.com/doc/refman/8.0/en/sys-extract-schema-from-file-name.html

It provides a convenient way to display schema names, which can be more easily understood than full path names, and can be used in joins against object schema names. Given a file path name, returns the path component that represents the schema name. This function assumes that the file name lies within the schema ...

30.4.5.2 The extract_table_from_file_name() Function

https://dev.mysql.com/doc/refman/8.0/en/sys-extract-table-from-file-name.html

It provides a convenient way to display table names, which can be more easily understood than full path names, and can be used in joins against object table names. Given a file path name, returns the path component that represents the table name.

27.5.1 View Syntax

https://dev.mysql.com/doc/refman/8.0/en/view-syntax.html

The CREATE VIEW statement creates a new view (see Section 15.1.23, “CREATE VIEW Statement”). To alter the definition of a view or drop a view, use ALTER VIEW (see Section 15.1.11, “ALTER VIEW Statement”), or DROP VIEW (see Section 15.1.35, ...

10.2.1.21 Window Function Optimization

https://dev.mysql.com/doc/refman/8.0/en/window-function-optimization.html

Semijoins are not applicable to window function optimization because semijoins apply to subqueries in WHERE and JOIN ... Window functions affect the strategies the optimizer considers: Derived table merging for a subquery is disabled if the ...

15.3.8.3 Restrictions on XA Transactions

https://dev.mysql.com/doc/refman/8.0/en/xa-restrictions.html

For XA START, the JOIN and RESUME clauses are recognized but have no effect. XA transaction support is limited to the InnoDB storage engine. For “external XA,” a MySQL server acts as a Resource Manager and client programs act as Transaction ...