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https://dev.mysql.com/doc/refman/8.4/en/fetching-spatial-data.html
Fetching spatial data in internal format: Fetching geometry values using internal format can be useful in table-to-table transfers: CREATE TABLE geom2 (g GEOMETRY) SELECT g FROM geom; Fetching spatial data in WKT format: The ST_AsText() function ...
https://dev.mysql.com/doc/refman/8.4/en/flow-control-functions.html
The second syntax returns the result for the first condition that is true. If no comparison or condition is true, the result after ELSE is returned, or NULL if there is no ELSE part. Note The syntax of the CASE operator described here differs ...
https://dev.mysql.com/doc/refman/8.4/en/forcing-innodb-recovery.html
Before doing so, ensure that you have a backup copy of your database in case you need to recreate it. After using this value, be prepared to drop and recreate all secondary indexes. With an innodb_force_recovery value of 3 or less you can DROP or ...
https://dev.mysql.com/doc/refman/8.4/en/function-optimization.html
A function is nondeterministic if, given fixed values for its arguments, it can return different results for different invocations. If a function is tagged nondeterministic, a reference to it in a WHERE clause is evaluated for every row (when ...
https://dev.mysql.com/doc/refman/8.4/en/generated-column-index-optimizations.html
For example: CREATE TABLE t1 (f1 INT, gc INT AS (f1 + 1) STORED, INDEX (gc)); The generated column, gc, is defined as the expression f1 + 1. The column is also indexed and the optimizer can take that index into account during execution plan ...
https://dev.mysql.com/doc/refman/8.4/en/geometry-well-formedness-validity.html
Spatial import functions that parse WKT or WKB values raise an error for attempts to create a geometry that is not syntactically well-formed. For geometry values, MySQL distinguishes between the concepts of syntactically well-formed and ...
https://dev.mysql.com/doc/refman/8.4/en/gone-away.html
If you want to create a bug report regarding this problem, be sure that you include the following information: Indicate whether the MySQL server died. This section also covers the related Lost connection to server during query error. The most ...
https://dev.mysql.com/doc/refman/8.4/en/group-by-functional-dependence.html
The following discussion provides several examples of the ways in which MySQL detects functional dependencies. The examples use this notation: {X} -> {Y} Understand this as “X uniquely determines Y,” which also means that Y is functionally ...
https://dev.mysql.com/doc/refman/8.4/en/group-by-modifiers.html
The GROUP BY clause permits a WITH ROLLUP modifier that causes summary output to include extra rows that represent higher-level (that is, super-aggregate) summary operations. ROLLUP thus enables you to answer questions at multiple levels of ...
https://dev.mysql.com/doc/refman/8.4/en/group-by-optimization.html
The most general way to satisfy a GROUP BY clause is to scan the whole table and create a new temporary table where all rows from each group are consecutive, and then use this temporary table to discover groups and apply aggregate functions (if ...