1In a federated system,table-namemust identify a table in the federated database. It cannot identify a data source table. 2Ifnicknameis specified, the CREATE INDEX statement creates an index specification. In this case, INCLUDE,xml-index-specification, CLUSTER, EXTEND USING, PCTFREE, MINPCTUSED...
<index_column_name> ::= <column_name> [ASC|DESC] ExamplesSQL Tutorial, IndexesExplanationIndexes provide access to the table data via non-key columns. Maintaining these indexes, however, can be quite complex in the case of an INSERT, UPDATE, or DELETE statement....
Creates a unique index on a table. Duplicate values are not allowed:CREATE UNIQUE INDEX index_name ON table_name (column1, column2, ...); MySQL CREATE INDEX ExampleThe SQL statement below creates an index named "idx_lastname" on the "LastName" column in the "Persons" table:CREATE ...
You can create a multi-valued index in a CREATE TABLE, ALTER TABLE, or CREATE INDEX statement. This requires using CAST(... AS ... ARRAY) in the index definition, which casts same-typed scalar values in a JSON array to an SQL data type array. A virtual column is then generated trans...
For more information about how to create this index, see CONSTRAINT clause.RemarksUse the CREATE TABLE statement to define a new table and its fields and field constraints. If NOT NULL is specified for a field, new records are required to have valid data in that ...
See Section 13.7.5.22, “SHOW INDEX Statement”. KEY | INDEX KEY is normally a synonym for INDEX. The key attribute PRIMARY KEY can also be specified as just KEY when given in a column definition. This was implemented for compatibility with other database systems. UNIQUE A UNIQUE ...
CREATE INDEX index1 ON schema1.table1 (column1); 在表上创建聚集索引,并为表使用由 3 个部分组成的名称 SQL 复制 CREATE CLUSTERED INDEX index1 ON database1.schema1.table1 (column1); 使用唯一约束创建非聚集索引并指定排序顺序 SQL 复制 CREATE UNIQUE INDEX index1 ON schema1.table1 (column...
KEY_BLOCK_SIZEis not supported at the index level forInnoDBtables. SeeSection 13.1.18, “CREATE TABLE Statement”. index_type Some storage engines permit you to specify an index type when creating an index. For example: CREATE TABLE lookup (id INT) ENGINE = MEMORY; ...
For additional information about index prefixes, see Section 13.1.14, “CREATE INDEX Statement”. Only the InnoDB and MyISAM storage engines support indexing on BLOB and TEXT columns. For example: CREATE TABLE test (blob_col BLOB, INDEX(blob_col(10))); As of MySQL 5.7.17, if a ...
CREATE [TEMPORARY] TABLEtable(field1 type[(size)] [NOT NULL] [WITH COMPRESSION | WITH COMP] [index1] [,field2type[(size)] [NOT NULL] [index2] [, …]] [, CONSTRAINTmultifieldindex[, …]]) The CREATE TABLE statement has these parts: ...