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Displaying 1 to 10 of 988 total results
https://dev.mysql.com/doc/refman/5.7/en/create-table-generated-columns.html
Values of a generated column are computed from an expression included in the column definition. Generated columns are supported by the NDB storage engine beginning with MySQL NDB Cluster 7.5.3. Generated column definitions have this syntax: col_name ...The VIRTUAL or STORED keyword indicates how column values are stored, which has implications for column use: VIRTUAL: Column values are not stored, but are evaluated when rows are read, immediately after any BEFORE ...
https://dev.mysql.com/doc/refman/5.7/en/alter-table-generated-columns.html
ALTER TABLE operations permitted for generated columns are ADD, MODIFY, and CHANGE. CREATE TABLE t1 (c1 INT); ALTER TABLE t1 ADD COLUMN c2 INT GENERATED ALWAYS AS (c1 + 1) STORED; The data type and expression of generated columns can be modified.
https://dev.mysql.com/doc/refman/5.7/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. This occurs if the WHERE, ORDER BY, or GROUP BY clause refers to an expression that matches the definition ...The column is also indexed and the optimizer can take that index into account during execution plan ...You can ...
https://dev.mysql.com/doc/refman/5.7/en/glossary.html
The values from such a column can be used as lookup keys in various contexts, and because they are auto-generated there is no reason to ever change them; for this reason, primary key columns are often specified as auto-incrementing. base column A ...
https://dev.mysql.com/doc/refman/5.7/en/create-table.html
You can work around this restriction by creating an index on a generated column that extracts a scalar value from the JSON column. See Indexing a Generated Column to Provide a JSON Column Index, for a detailed example. If the NO_AUTO_VALUE_ON_ZERO ...LIKE to create an empty table based on the definition of another table, including any column attributes and indexes defined in the original table: CREATE TABLE new_tbl LIKE orig_tbl; For more information, see Section 13.1.18.3, “CREATE TABLE ...
https://dev.mysql.com/doc/refman/5.7/en/partitioning-columns-range.html
Range columns partitioning is similar to range partitioning, but enables you to define partitions using ranges based on multiple column values. In addition, you can define the ranges using columns of types other than integer types. RANGE COLUMNS ...
https://dev.mysql.com/doc/refman/5.7/en/create-table-secondary-indexes.html
A secondary index may be created on one or more virtual columns or on a combination of virtual columns and regular columns or stored generated columns. When a secondary index is created on a virtual generated column, generated column values are ...A ...The data length of logged values is limited by the index key limit of 767 bytes for COMPACT and REDUNDANT row formats, and 3072 bytes for DYNAMIC and COMPRESSED row ...
https://dev.mysql.com/doc/refman/5.7/en/information-schema-columns-table.html
GENERATION_EXPRESSION For generated columns, displays the expression used to compute column values. For information about generated columns, see Section 13.1.18.7, “CREATE TABLE and Generated Columns”. The COLUMNS table has these columns: ...
https://dev.mysql.com/doc/refman/5.7/en/alter-table.html
For information about generated columns, see Section 13.1.8.2, “ALTER TABLE and Generated Columns”. The WITHOUT VALIDATION and WITH VALIDATION clauses affect whether ALTER TABLE performs an in-place operation for virtual generated column ...| ...
https://dev.mysql.com/doc/refman/5.7/en/show-columns.html
SHOW [FULL] {COLUMNS | FIELDS} {FROM | IN} tbl_name [{FROM | IN} db_name] [LIKE 'pattern' | WHERE expr] SHOW COLUMNS displays information about the columns in a given table. SHOW COLUMNS displays information only for those columns for which you ...
Displaying 1 to 10 of 988 total results