What is the method for performing multiple table associations in Mybatis?

There are several methods for performing multi-table association queries in MyBatis.

1. Utilize nested queries: Perform multi-table relational queries in the Mapper file using nested queries. Associate the query results of other tables by configuring association or collection in the resultMap.
2. Utilize nested result mapping: Perform multi-table join queries in the Mapper file by using nested result mapping. Connect the query results of other tables by configuring nested result maps in the resultMap.
3. Use one-to-one association: Perform a multi-table join query in the Mapper file using a one-to-one association. Link the results of the query with other tables by configuring the ‘one’ tag in the resultMap.
4. Utilize one-to-many association: Perform a multi-table join query using one-to-many association in the Mapper file. Use the collection tag in the resultMap configuration to link the query results from other tables.
5. Utilizing dynamic SQL: Conducting multi-table join queries through the use of dynamic SQL. By utilizing tags such as ‘if’, ‘choose’, ‘when’, and ‘otherwise’ in the Mapper file to dynamically concatenate SQL statements based on conditions for multi-table join queries.

These are some common methods, and the choice of which method to use depends on the business needs and the relationship of the data tables. In actual development, the most suitable way for performing multi-table join queries can be chosen based on specific circumstances.