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26 mar 2013 · Well, you can create a function-based index on the expression you've used in your query: create index myindex on mytable (fld1 || '%'); However, it's unlikely to be of any benefit to this query. I'd say your normal non-unique index on fld1 will work just as well as the function-based index.
12 sty 2023 · Database indexes typically contain information about data in a specific column of the database table. With the introduction of functional indexes in MySQL 8.0.13, we can now create indexes based on the result of an expression or function.
15 maj 2012 · Yes, we can create functional index in MySQL. This feature is available from MySQL 8.0.13. (Other RDBMS have this feature in its earlier releases But MySQL introduced it in its release 8.0.13).
A function-based index calculates the result of a function that involves one or more columns and stores that result in the index. The following shows the syntax of creating a function-based index: CREATE INDEX index_name ON table_name (expression); Code language: SQL (Structured Query Language) (sql)
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.
The following code samples give an example of the use of Function-Based Indexes. Build Test Table; Build Regular Index; Build Function-Based Index; Concatenated Columns; Build Test Table. First we build a test table and populate it with enough data so that use of an index would be advantageous.
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.
