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https://dev.mysql.com/doc/refman/8.4/en/gis-wkb-functions.html
Unless otherwise specified, functions in this section handle their geometry arguments as follows: If the WKB or SRID argument is NULL, the return value is NULL. If the options argument is NULL, the return value is NULL. These functions take as ...
https://dev.mysql.com/doc/refman/8.4/en/group-by-handling.html
The query is invalid if name is not a primary key of t or a unique NOT NULL column. SQL-92 and earlier does not permit queries for which the select list, HAVING condition, or ORDER BY list refer to nonaggregated columns that are not named in the ...
https://dev.mysql.com/doc/refman/8.4/en/innodb-information-schema-system-tables.html
row *************************** TABLE_ID: 71 NAME: col1 POS: 0 MTYPE: 6 PRTYPE: 1027 LEN: 4 HAS_DEFAULT: 0 DEFAULT_VALUE: NULL *************************** 2. row *************************** TABLE_ID: 71 NAME: col2 POS: 1 MTYPE: 2 PRTYPE: 524542 LEN: ... You can extract metadata about schema objects managed by InnoDB using InnoDB INFORMATION_SCHEMA ...
https://dev.mysql.com/doc/refman/8.4/en/innodb-troubleshooting-datadict.html
A warning is issued indicating that InnoDB is attempting to import the file without schema verification. Information about table definitions is stored in the InnoDB data dictionary. If you move data files around, dictionary data can become ...
https://dev.mysql.com/doc/refman/8.4/en/locking-functions.html
Returns 1 if the lock was obtained successfully, 0 if the attempt timed out (for example, because another client has previously locked the name), or NULL if an error occurred (such as running out of memory or the thread was killed with mysqladmin ...
https://dev.mysql.com/doc/refman/8.4/en/mysql-cluster-ndbinfo-operations-per-fragment.html
The operations_per_fragment table provides information about the operations performed on individual fragments and fragment replicas, as well as about some of the results from these operations. This currently has the following formats: Base table: ...
https://dev.mysql.com/doc/refman/8.4/en/optimizing-innodb-bulk-data-loading.html
For optimal performance when loading data into an InnoDB FULLTEXT index, follow this set of steps: Define a column FTS_DOC_ID at table creation time, of type BIGINT UNSIGNED NOT NULL, with a unique index named FTS_DOC_ID_INDEX. For example: CREATE ... These performance tips supplement the general guidelines for fast inserts in Section 10.2.5.1, “Optimizing INSERT ...
https://dev.mysql.com/doc/refman/8.4/en/performance-schema-firewall-groups-table.html
The value is NULL, or a non-NULL account that has the format user_name@host_name: If the value is NULL, the firewall records allowlist rules for statements received from any account that is a member of the group. If the value is non-NULL, the ...
https://dev.mysql.com/doc/refman/8.4/en/performance-schema-timing.html
If an enabled instrument is not timed, events produced by the instrument have NULL for the TIMER_START, TIMER_END, and TIMER_WAIT timer values. Events that have not yet completed have an END_EVENT_ID value of NULL. Events are collected by means of ...
https://dev.mysql.com/doc/refman/8.4/en/rename-table.html
row *************************** Table: t3 Create Table: CREATE TABLE `t3` ( `i1` int(11) DEFAULT NULL, `i2` int(11) DEFAULT NULL, CONSTRAINT `t3_chk_1` CHECK ((`i1` > 0)), CONSTRAINT `t3_chk_2` CHECK ((`i2` < 0)) ) ENGINE=InnoDB DEFAULT ... RENAME ...