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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.
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;
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: CREATEINDEX idx_c4 ON t (c4);Code language:SQL (Structured Query Language)(sql)
18 cze 2024 · Learn how to create a MySQL table with an index, how to add an index to an existing table, and how to troubleshoot common indexing issues.
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.
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.
