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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;
22 lis 2010 · To add an index to a table without a lock resulting on UPDATE/ INSERT, the following statement format can be used: ALTER TABLE my_table ADD INDEX my_table__idx (my_column), ALGORITHM=INPLACE, LOCK=NONE;
CREATE INDEX enables you to add indexes to existing tables. CREATE INDEX is mapped to an ALTER TABLE statement to create indexes. See Section 13.1.9, “ALTER TABLE Statement”. CREATE INDEX cannot be used to create a PRIMARY KEY; use ALTER TABLE instead.
10.3.1 How MySQL Uses Indexes. Indexes are used to find rows with specific column values quickly. Without an index, MySQL must begin with the first row and then read through the entire table to find the relevant rows. The larger the table, the more this costs. If the table has an index for the columns in question, MySQL can quickly determine ...
MySQL CREATE INDEX Statement. 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.
19 wrz 2012 · My query would give you the count of indexes present on a table with a particular index_name. Based on that count, you can decide whether to issue a CREATE INDEX command or not. Tested on MySQL version 5.5. MariaDB supports IF NOT EXISTS syntax. You can use CREATE INDEX IF NOT EXISTS there.
To add an index for a column or a set of columns, you use the CREATE INDEX statement as follows: CREATE INDEX index_name ON table_name (column_list) Code language: SQL (Structured Query Language) ( sql )
