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https://dev.mysql.com/doc/refman/8.4/en/explain-output.html
The value can be NULL if the row refers to the union result of other rows. If this column is NULL (or undefined in JSON-formatted output), there are no relevant indexes. If key is NULL, MySQL found no index to use for executing the query more ...
https://dev.mysql.com/doc/mysql-shell/9.4/en/mysql-shell-utilities-dump-instance-schema.html
For the table dump utility, schema specifies the schema that contains the items to be dumped, and tables is an array of strings specifying the tables or views to be dumped. maxRate: "string" The maximum number of bytes per second per thread for data ... MySQL Shell's instance dump utility util.dumpInstance() and schema dump utility util.dumpSchemas(), support the export of all schemas or a selected schema from an on-premise MySQL instance into an Oracle Cloud Infrastructure Object Storage bucket or a set of local ...
https://dev.mysql.com/doc/refman/8.4/en/glossary.html
Although the Oracle database allows a NULL value to be concatenated with a string, InnoDB treats the result of such an operation as NULL. It provides useful information for the query optimizer, because the column is known to be not null and with ...
https://dev.mysql.com/doc/refman/8.4/en/create-table.html
An example statement using this syntax is shown here (emphasized text): CREATE TABLE t1 ( c1 INT NOT NULL AUTO_INCREMENT PRIMARY KEY, c2 VARCHAR(100), c3 VARCHAR(100) ) ENGINE=NDB COMMENT="NDB_TABLE=READ_BACKUP=0,PARTITION_BALANCE=FOR_RP_BY_NODE"; ...Prefix lengths are given in characters for nonbinary string types and in bytes for binary string ...
https://dev.mysql.com/doc/refman/8.4/en/aggregate-functions.html
The result type depends on whether the function argument values are evaluated as binary strings or numbers: Binary-string evaluation occurs when the argument values have a binary string type, and the argument is not a hexadecimal literal, bit ...
https://dev.mysql.com/doc/refman/8.4/en/mysql-cluster-ndbinfo.html
row *************************** Engine: BLACKHOLE Support: YES Comment: /dev/null storage engine (anything you write to it disappears) Transactions: NO XA: NO Savepoints: NO *************************** 8. ndbinfo is a database containing ...
https://dev.mysql.com/doc/refman/8.4/en/derived-tables.html
row *************************** id: 1 select_type: PRIMARY table: <derived2> partitions: NULL type: system possible_keys: NULL key: NULL key_len: NULL ref: NULL rows: 1 filtered: 100.00 Extra: NULL *************************** 2. row ...For ...
https://dev.mysql.com/doc/internals/en/vc-plus-plus-files-directory.html
VC++Files includes a complete environment to compile MySQL with the VC++ compiler. To use it, just copy the files on this directory; the make_win_src_distribution.sh script uses these files to create a Windows source installation. This directory has ...
https://dev.mysql.com/doc/refman/8.4/en/nested-join-optimization.html
In some of the following examples, NULL where a table name appears means a row in which NULL is used for each column of that table. For example, t1||t2||NULL indicates a row constructed by concatenating the columns of rows t1 and t2, and NULL for ...
https://dev.mysql.com/doc/refman/8.4/en/get-diagnostics.html
The first value is a non-NULL string and the second is NULL. For example, the handler maps the NULL insert to an empty-string insert and displays the result. The empty row results from the attempt to insert NULL that was mapped to an empty-string ...