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https://dev.mysql.com/doc/refman/8.4/en/checksum-table.html
If you run CHECKSUM TABLE against a view, the Checksum value is always NULL, and a warning is returned. For a nonexistent table, CHECKSUM TABLE returns NULL and generates a warning. If the table does not meet all these conditions, the QUICK method ...[QUICK | EXTENDED] CHECKSUM TABLE reports a checksum for the contents of a ...
https://dev.mysql.com/doc/refman/8.4/en/converting-tables-to-innodb.html
Consider using an auto-increment column if there is not another stable, unique, non-null, numeric column to use. You can designate the former primary key columns as UNIQUE NOT NULL to enforce the same constraints as the PRIMARY KEY clause, that is, ... If you have MyISAM tables that you want to convert to InnoDB for better reliability and scalability, review the following guidelines and tips before ...
https://dev.mysql.com/doc/refman/8.4/en/descending-indexes.html
MySQL supports descending indexes: DESC in an index definition is no longer ignored but causes storage of key values in descending order. Previously, indexes could be scanned in reverse order but at a performance penalty. A descending index can be ...
https://dev.mysql.com/doc/refman/8.4/en/examples.html
Here are examples of how to solve some common problems with MySQL. Some of the examples use the table shop to hold the price of each article (item number) for certain traders (dealers). Supposing that each trader has a single fixed price per ...
https://dev.mysql.com/doc/refman/8.4/en/expressions.html
This section lists the grammar rules that expressions must follow in MySQL and provides additional information about the types of terms that may appear in expressions. Expression Syntax Expression Term Notes Temporal Intervals Expression Syntax The ...
https://dev.mysql.com/doc/refman/8.4/en/federated-create-connection.html
For example: CREATE TABLE federated_table ( id INT(20) NOT NULL AUTO_INCREMENT, name VARCHAR(32) NOT NULL DEFAULT '', other INT(20) NOT NULL DEFAULT '0', PRIMARY KEY (id), INDEX name (name), INDEX other_key (other) ) ENGINE=FEDERATED DEFAULT ... To ...
https://dev.mysql.com/doc/refman/8.4/en/federated-create-server.html
If you are creating a number of FEDERATED tables on the same server, or if you want to simplify the process of creating FEDERATED tables, you can use the CREATE SERVER statement to define the server connection parameters, just as you would with the ...
https://dev.mysql.com/doc/refman/8.4/en/federated-create.html
To create a FEDERATED table you should follow these steps: Create the table on the remote server. Alternatively, make a note of the table definition of an existing table, perhaps using the SHOW CREATE TABLE statement. Create the table on the local ...
https://dev.mysql.com/doc/refman/8.4/en/functions.html
Expressions can be written using values from several sources, such as literal values, column values, NULL, variables, built-in functions and operators, loadable functions, and stored functions (a type of stored object). An expression that contains ... Expressions can be used at several points in SQL statements, such as in the ORDER BY or HAVING clauses of SELECT statements, in the WHERE clause of a SELECT, DELETE, or UPDATE statement, or in SET ...
https://dev.mysql.com/doc/refman/8.4/en/gis-general-property-functions.html
Unless otherwise specified, functions in this section handle their geometry arguments as follows: If any argument is NULL, the return value is NULL. The functions listed in this section do not restrict their argument and accept a geometry value of ...