mybatis union用法
MyBatis does not have a specific "union" keyword or function like SQL. However, you can achieve the same result by using multiple select statements and combining the results in your application code.
Here's an example of how you can use union in MyBatis:
1. Create a mapper XML file (e.g., `l`) with the following content:
xml
<mapper namespace="ample.ExampleMapper">
  <select id="getUnionResults" resultType="ample.Result">
    SELECT column1, column2 FROM table1
    UNION
    SELECT column1, column2 FROM table2
  </select>
</mapper>
2. Create a Java interface (e.g., `ExampleMapper.java`) with the following content:
java
ample;
public interface ExampleMapper {
  List<Result> getUnionResults();
}
3. Create a Java class (e.g., `Result.java`) to represent the result of the union query:
java
ample;
public class Result {
  private String column1;represent的用法
  private String column2;
  getters and setters
}
4. Use the mapper in your application code to execute the query and retrieve the results:
java
ExampleMapper exampleMapper = Mapper(ExampleMapper.class);
List<Result> results = UnionResults();
In this example, the `getUnionResults` method in the `ExampleMapper` interface executes the union query defined in the mapper XML file. The result is a list of `Result` objects, where each object represents a row returned by the query.
Note that you can customize the SQL query in the mapper XML file to fit your specific requirements.

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