How can Mybatis return a result set from a stored proce…

There are several ways in which MyBatis can return result sets from stored procedures.

1. Using OUT Parameters: You can define OUT parameters in a stored procedure and then use #{outParamName, mode=OUT, jdbcType=CURSOR} in the MyBatis Mapper to receive the result set. For example:

<select id="callProcedure" statementType="CALLABLE">
  {call get_users(#{outParam, mode=OUT, jdbcType=CURSOR})}
</select>

In Java code, you can obtain the result set by calling the getConnection() method and process it using the ResultSetHandler.

1. Using cursor type result sets: Some databases support returning results as a cursor, which can be defined in a stored procedure as a cursor type to return the result set, and then mapped in the MyBatis Mapper using #resultType or #resultMap. For example:

<select id="callProcedure" statementType="CALLABLE" resultType="User">
  {call get_users()}
</select>

Among them, resultType specifies the mapping type of the result set, which can be a simple Java object or a ResultMap.

1. Using temporary tables: you can create a temporary table in a stored procedure and insert the result set into that table, then perform query operations on that temporary table in the MyBatis Mapper. For example:

<insert id="callProcedure" statementType="CALLABLE">
  {call get_users()}
</insert>

<select id="queryTempTable" resultType="User">
  SELECT * FROM temp_table
</select>

In Java code, first call the procedure to invoke the stored procedure, then execute queryTempTable to retrieve the result set.

It is important to note that the specific implementation may vary depending on the database type and version, so it is recommended to refer to the relevant database and MyBatis documentation based on the actual situation.