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https://dev.mysql.com/doc/refman/5.7/en/myisamchk-table-info.html
Auto increment key, Last value The key number associated the table's AUTO_INCREMENT column, and the most recently generated value for this column. “Record” and “row” are synonymous, as are “field” and “column.” The initial part of ...
https://dev.mysql.com/doc/refman/5.7/en/json-search-functions.html
column->path In MySQL 5.7.9 and later, the -> operator serves as an alias for the JSON_EXTRACT() function when used with two arguments, a column identifier on the left and a JSON path (a string literal) on the right that is evaluated against the ...
https://dev.mysql.com/doc/refman/5.7/en/create-table-select.html
SELECT, the destination table does not preserve information about whether columns in the selected-from table are generated columns. The SELECT part of the statement cannot assign values to generated columns in the destination table. You can create ...The ENGINE option is part of the CREATE TABLE statement, and should not be used following the SELECT; this would result in a syntax ...
https://dev.mysql.com/doc/refman/5.7/en/partitioning-key.html
KEY takes only a list of zero or more column names. Any columns used as the partitioning key must comprise part or all of the table's primary key, if the table has one. Where no column name is specified as the partitioning key, the table's primary ... Partitioning by key is similar to partitioning by hash, except that where hash partitioning employs a user-defined expression, the hashing function for key partitioning is supplied by the MySQL ...
https://dev.mysql.com/doc/refman/5.7/en/optimize-character.html
The GROUP BY and ORDER BY clauses can generate temporary tables, and these temporary tables can use the MEMORY storage engine if the original table does not contain any BLOB columns. For character and string columns, follow these guidelines: Use ...
https://dev.mysql.com/doc/refman/5.7/en/create-index.html
For more information, see Section 13.1.18.8, “Secondary Indexes and Generated Columns”. For example (col1, col2, col3) specifies a multiple-column index with index keys consisting of values from col1, col2, and col3. Additionally, BLOB and TEXT ... CREATE [UNIQUE | FULLTEXT | SPATIAL] INDEX index_name [index_type] ON tbl_name (key_part,...) [index_option] [algorithm_option | lock_option] ...
https://dev.mysql.com/doc/refman/5.7/en/information-schema-innodb-sys-indexes-table.html
0 = nonunique secondary index; 1 = automatically generated clustered index (GEN_CLUST_INDEX); 2 = unique nonclustered index; 3 = clustered index; 32 = full-text index; 64 = spatial index; 128 = secondary index on a virtual generated column. The ...
https://dev.mysql.com/doc/refman/5.7/en/innodb-persistent-stats.html
If innodb_stats_auto_recalc is disabled, you can ensure the accuracy of optimizer statistics by executing the ANALYZE TABLE statement after making substantial changes to indexed columns. When an index is added to an existing table, or when a column ... The persistent optimizer statistics feature improves plan stability by storing statistics to disk and making them persistent across server restarts so that the optimizer is more likely to make consistent choices each time for a given ...
https://dev.mysql.com/doc/refman/5.7/en/precision-math-expressions.html
In strict SQL mode, for INSERT into a column with an exact data type (DECIMAL or integer), a number is inserted with its exact value if it is within the column range. Inserts into numeric columns are affected by the SQL mode, which is controlled by ... With precision math, exact-value numbers are used as given whenever ...
https://dev.mysql.com/doc/refman/5.7/en/range-optimization.html
The key_len column in the EXPLAIN output indicates the maximum length of the key prefix used. Equality Range Optimization of Many-Valued Comparisons Consider these expressions, where col_name is an indexed column: col_name IN(val1, ..., valN) ...