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https://dev.mysql.com/doc/refman/8.4/en/descending-indexes.html
For InnoDB full-text search, this means that the index required on the FTS_DOC_ID column of the indexed table cannot be defined as a descending index. MySQL supports descending indexes: DESC in an index definition is no longer ignored but causes ...
https://dev.mysql.com/doc/refman/8.4/en/error-message-language.html
This applies to messages the server writes to the error log and sends to clients. To select the language in which the server writes error messages, follow the instructions in this section. The server searches for the error message file using these ... By default, mysqld produces error messages in English, but they can be displayed instead in any of several other languages: Czech, Danish, Dutch, Estonian, French, German, Greek, Hungarian, Italian, Japanese, Korean, Norwegian, Norwegian-ny, Polish, Portuguese, Romanian, Russian, Slovak, Spanish, or ...
https://dev.mysql.com/doc/refman/8.4/en/expressions.html
This section lists the grammar rules that expressions must follow in MySQL and provides additional information about the types of terms that may appear in expressions. Intervals have this syntax: INTERVAL expr unit expr represents a quantity. This ...Expression Syntax Expression Term Notes Temporal Intervals Expression Syntax The following grammar rules define expression syntax in ...
https://dev.mysql.com/doc/refman/8.4/en/full-text-adding-collation.html
This section describes how to add a user-defined collation for full-text searches using the built-in full-text parser. In the following array, this is the element in the fourth row down, third value from the end. Warning User-defined collations are ...
https://dev.mysql.com/doc/refman/8.4/en/group-by-modifiers.html
MySQL supports an additional, alternative syntax for this modifier, as shown in Section 15.2.13, “SELECT Statement”. In this case, each time there is a change in value in any but the last grouping column, the query produces an extra ... The ...
https://dev.mysql.com/doc/refman/8.4/en/index-condition-pushdown-optimization.html
If we know a person's zipcode value but are not sure about the last name, we can search like this: SELECT * FROM people WHERE zipcode='95054' AND lastname LIKE '%etrunia%' AND address LIKE '%Main Street%'; MySQL can use the index to scan through ...
https://dev.mysql.com/doc/refman/8.4/en/information-schema-innodb-table-reference.html
The following table summarizes INFORMATION_SCHEMA InnoDB tables. For greater detail, see the individual table descriptions. Table 28.3 INFORMATION_SCHEMA InnoDB Tables Table Name Description INNODB_BUFFER_PAGE Pages in InnoDB buffer pool ...
https://dev.mysql.com/doc/refman/8.4/en/information-schema-optimization.html
This includes values such as database and table names, table types, and storage engines. Consider this statement, which identifies collations for the utf8mb4 character set: mysql> SELECT COLLATION_NAME FROM ... Applications that monitor databases ...
https://dev.mysql.com/doc/refman/8.4/en/information-schema-table-reference.html
The following table summarizes all available INFORMATION_SCHEMA tables. For greater detail, see the individual table descriptions. Table 28.1 INFORMATION_SCHEMA Tables Table Name Description Deprecated ADMINISTRABLE_ROLE_AUTHORIZATIONS Grantable ...
https://dev.mysql.com/doc/refman/8.4/en/innochecksum.html
This tool reads an InnoDB tablespace file, calculates the checksum for each page, compares the calculated checksum to the stored checksum, and reports mismatches, which indicate damaged pages. Because checksum mismatches cause InnoDB to deliberately ...It was originally developed to speed up verifying the integrity of tablespace files after power outages but can also be used after file ...