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https://dev.mysql.com/doc/refman/8.4/en/charset-metadata.html
Thus column names, database names, user names, version names, and most of the string results from SHOW are metadata. Otherwise, neither the SHOW statements nor SELECT statements for tables in INFORMATION_SCHEMA would work properly because different ... Metadata is “the data about the data.” Anything that describes the database—as opposed to being the contents of the database—is ...
https://dev.mysql.com/doc/refman/8.4/en/clone-plugin-stop.html
On the recipient MySQL server instance, you can retrieve the processlist identifier (PID) for a cloning operation from the PID column of the clone_status table. If necessary, you can stop a cloning operation with a KILL QUERY processlist_id ...
https://dev.mysql.com/doc/refman/8.4/en/counting-rows.html
Counting the total number of animals you have is the same question as “How many rows are in the pet table?” because there is one record per pet. COUNT(*) counts the number of rows, so the query to count your animals looks like this: mysql> ...
https://dev.mysql.com/doc/refman/8.4/en/create-spatial-reference-system.html
With CREATE OR REPLACE syntax, any existing SRS definition with the same SRID value is replaced, unless the SRID value is used by some column in an existing table. To identify which column or columns use the SRID, use this query, replacing 4326 with ...srs_attribute: { NAME 'srs_name' | DEFINITION 'definition' | ORGANIZATION 'org_name' IDENTIFIED BY org_id | DESCRIPTION 'description' } srid, org_id: 32-bit unsigned integer This statement creates a spatial reference system (SRS) definition and stores it in the data ...
https://dev.mysql.com/doc/refman/8.4/en/drop-spatial-reference-system.html
If the SRID value is used by some column in an existing table, an error occurs. To identify which column or columns use the SRID, use this query: SELECT * FROM INFORMATION_SCHEMA.ST_GEOMETRY_COLUMNS WHERE SRS_ID=4326; SRID values must be in the ...
https://dev.mysql.com/doc/refman/8.4/en/example-foreign-keys.html
A foreign key relationship involves a parent table that holds the initial column values, and a child table with column values that reference the parent column values. This following example relates parent and child tables through a single-column ...
https://dev.mysql.com/doc/refman/8.4/en/extensions-to-ansi.html
Use of index names, indexes on a prefix of a column, and use of INDEX or KEY in CREATE TABLE statements. You don't need to name all selected columns in the GROUP BY clause. To perform case-sensitive comparisons instead, you should declare your ...
https://dev.mysql.com/doc/refman/8.4/en/faqs-mysql-cluster.html
You must also remember to account for any column indexes as follows: Each primary key or hash index created for an NDBCLUSTER table requires 21−25 bytes per record. Spatial indexes are not supported (although spatial columns can be used). This ...
https://dev.mysql.com/doc/refman/8.4/en/floating-point-types.html
A precision from 0 to 23 results in a 4-byte single-precision FLOAT column. A precision from 24 to 53 results in an 8-byte double-precision DOUBLE column. For example, a column defined as FLOAT(7,4) is displayed as -999.9999. MySQL performs rounding ... The FLOAT and DOUBLE types represent approximate numeric data ...
https://dev.mysql.com/doc/refman/8.4/en/group-replication-replication-group-members.html
The MEMBER_STATE column shows one of the Section 20.4.2, “Group Replication Server States”, in this case it shows that all three members in this group are ONLINE, and the MEMBER_ROLE column shows that there are two secondaries, and a single ...