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The CREATE INDEX statement is used to create indexes in tables. Indexes are used to retrieve data from the database more quickly than otherwise. The users cannot see the indexes, they are just used to speed up searches/queries.
CREATE INDEX enables you to add indexes to existing tables. CREATE INDEX is mapped to an ALTER TABLE statement to create indexes. See Section 15.1.9, “ALTER TABLE Statement”. CREATE INDEX cannot be used to create a PRIMARY KEY; use ALTER TABLE instead.
To create an index for a column or a list of columns, you specify the index name, the table to which the index belongs, and the column list. For example, to add a new index for the column c4, you use the following statement: CREATE INDEX idx_c4 ON t(c4); Code language: SQL (Structured Query Language) (sql) By default, MySQL creates the B-Tree ...
27 cze 2024 · The MySQL CREATE INDEX statement is a DDL (Data Definition Language) statement used to create indexes on tables. It allows developers to optimize query performance by specifying which columns should be indexed.
You can use this syntax to add an index and control the kind of index (HASH or BTREE). create index your_index_name on your_table_name(your_column_name) using HASH; or. create index your_index_name on your_table_name(your_column_name) using BTREE;
Creating indexes – introduce the index concept and show you how to create an index for one or more columns of a table. Removing indexes – show you how to remove an existing index of a table. Listing table indexes – provide you with a statement to list all indexes or specific indexes of a table.
The CREATE INDEX statement is a fundamental SQL command used in MySQL databases to create indexes on tables. Indexes are data structures that help MySQL retrieve data from tables more efficiently.
