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https://dev.mysql.com/doc/refman/8.4/en/numeric-type-syntax.html
For integer data types, M indicates the minimum display width. Display width is unrelated to the range of values a type can store, as described in Section 13.1.6, “Numeric Type Attributes”. For floating-point and fixed-point data types, M is ...
https://dev.mysql.com/doc/refman/8.4/en/order-by-optimization.html
This section describes when MySQL can use an index to satisfy an ORDER BY clause, the filesort operation used when an index cannot be used, and execution plan information available from the optimizer about ORDER BY. An ORDER BY with and without ...
https://dev.mysql.com/doc/refman/8.4/en/partitioning-columns.html
The next two sections discuss COLUMNS partitioning, which are variants on RANGE and LIST partitioning. COLUMNS partitioning enables the use of multiple columns in partitioning keys. All of these columns are taken into account both for the purpose ...
https://dev.mysql.com/doc/refman/8.4/en/partitioning-hash.html
Partitioning by HASH is used primarily to ensure an even distribution of data among a predetermined number of partitions. To partition a table using HASH partitioning, it is necessary to append to the CREATE TABLE statement a PARTITION BY HASH ...
https://dev.mysql.com/doc/refman/8.4/en/partitioning-linear-hash.html
MySQL also supports linear hashing, which differs from regular hashing in that linear hashing utilizes a linear powers-of-two algorithm whereas regular hashing employs the modulus of the hashing function's value. We call this value V; it can be ...
https://dev.mysql.com/doc/refman/8.4/en/performance-schema-user-defined-functions-table.html
The user_defined_functions table contains a row for each loadable function registered automatically by a component or plugin, or manually by a CREATE FUNCTION statement. For information about operations that add or remove table rows, see Section ...
https://dev.mysql.com/doc/refman/8.4/en/row-constructor-optimization.html
For example, these two statements are semantically equivalent: SELECT * FROM t1 WHERE (column1,column2) = (1,1); SELECT * FROM t1 WHERE column1 = 1 AND column2 = 1; In addition, the optimizer handles both expressions the same way. The optimizer is ...
https://dev.mysql.com/doc/refman/8.4/en/show-create-table.html
SHOW CREATE TABLE tbl_name Shows the CREATE TABLE statement that creates the named table. To use this statement, you must have some privilege for the table. row *************************** Table: t Create Table: CREATE TABLE `t` ( `id` int NOT NULL ...
https://dev.mysql.com/doc/refman/8.4/en/show-index.html
SHOW [EXTENDED] {INDEX | INDEXES | KEYS} {FROM | IN} tbl_name [{FROM | IN} db_name] [WHERE expr] SHOW INDEX returns table index information. This statement requires some privilege for any column in the table. row *************************** Table: ...
https://dev.mysql.com/doc/refman/8.4/en/silent-column-changes.html
In some cases, MySQL silently changes column specifications from those given in a CREATE TABLE or ALTER TABLE statement. These might be changes to a data type, to attributes associated with a data type, or to an index specification. All changes are ...