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https://dev.mysql.com/doc/refman/8.4/en/exists-and-not-exists-subqueries.html
For the preceding example, if t2 contains any rows, even rows with nothing but NULL values, the EXISTS condition is TRUE. If a subquery returns any rows at all, EXISTS subquery is TRUE, and NOT EXISTS subquery is FALSE. For example: SELECT column1 ...
https://dev.mysql.com/doc/refman/8.4/en/extensions-to-ansi.html
MySQL Server supports some extensions that you are not likely to find in other SQL DBMSs. Be warned that if you use them, your code is most likely not portable to other SQL servers. For example, MySQL Server recognizes the STRAIGHT_JOIN keyword in ...
https://dev.mysql.com/doc/refman/8.4/en/fulltext-boolean.html
MySQL can perform boolean full-text searches using the IN BOOLEAN MODE modifier. With this modifier, certain characters have special meaning at the beginning or end of words in the search string. In the following query, the + and - operators ...
https://dev.mysql.com/doc/refman/8.4/en/fulltext-stopwords.html
The stopword list is loaded and searched for full-text queries using the server character set and collation (the values of the character_set_server and collation_server system variables). False hits or misses might occur for stopword lookups if the ...
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/gis-class-geometry.html
Exterior, interior, and boundary of an empty geometry are not defined (that is, they are represented by a NULL value). It is a noninstantiable class but has a number of properties, described in the following list, that are common to all geometry ...
https://dev.mysql.com/doc/refman/8.4/en/group-replication-configuring-ssl-for-recovery.html
If this system variable is set to NULL when TLSv1.3 is used (which is the default if you do not set the system variable), the ciphersuites that are enabled by default are allowed, as listed in Section 8.3.2, “Encrypted Connection TLS Protocols and ... Important When using the MySQL communication stack (group_replication_communication_stack=MYSQL) AND secure connections between members (group_replication_ssl_mode is not set to DISABLED), the security settings discussed in this section are applied not just to distributed recovery connections, but to group communications between members in ...
https://dev.mysql.com/doc/refman/8.4/en/group-replication-launching.html
It should show something like this: mysql> SHOW PLUGINS; +----------------------------+----------+--------------------+----------------------+-------------+ | Name | Status | Type | Library | License | ... It is first necessary to ensure that the ...
https://dev.mysql.com/doc/refman/8.4/en/group-replication-requirements.html
Every table that is to be replicated by the group must have a defined primary key, or primary key equivalent where the equivalent is a non-null unique key. Infrastructure Server Instance Configuration Server instances that you want to use for Group ...
https://dev.mysql.com/doc/refman/8.4/en/index-btree-hash.html
A search using col_name IS NULL employs indexes if col_name is indexed. Understanding the B-tree and hash data structures can help predict how different queries perform on different storage engines that use these data structures in their indexes, ...