ResultSets can not divide received lists - mybatis

Question

I have two ResultSets that both of theme has completely separated SELECT and has not any relation to each other. but MyBatis always try to mix the result.
Movie table
ID_
NAME_
YEAR_
1
Movie1
2020
2
Movie2
2008
3
Movie3
1988
Artist table
ID_
NAME_
1
John
2
Jane
Select:
<select id="selectMultiple" resultSets="movies,artists" resultMap="multipleQueriesResult" statementType="CALLABLE">
BEGIN
SELECT M.ID_ AS mId,
M.NAME_ AS mName,
M.YEAR_ AS mYear
FROM TestMyBatis.dbo.Movie AS M
END
BEGIN
SELECT A.ID_ AS aId,
A.NAME_ AS aName
FROM TestMyBatis.dbo.Artist AS A
END
</select>
ResultMap:
<resultMap id="multipleQueriesResult" type="DivideOut" autoMapping="true">
<collection property="movie"
ofType="Movie"
javaType="list"
resultSet="movies">
<id property="id" column="mId"/>
<result property="name" column="mName"/>
<result property="year" column="mYear"/>
</collection>
<collection property="artist"
ofType="Artist"
javaType="list"
resultSet="artists">
<id property="id" column="aId"/>
<result property="name" column="aName"/>
</collection>
</resultMap>
DivideOut:
public class DivideOut {
public List<Object> movie;
public List<Object> artist;
#Override
public String toString() {
return "DivideOut{" +
"movie=" + movie +
", artist=" + artist +
'}';
}
}
Expected Output:
[
DivideOut{movie=[Movie{id=1, name=Movie1, year=2020}], artist=[Artist{id=1, name='john}]},
DivideOut{movie=[Movie{id=1, name=Movie1, year=2020}], artist=[Artist{id=2, name='jane}]},
DivideOut{movie=[Movie{id=2, name=Movie2, year=2008}], artist=[Artist{id=1, name='john}]},
DivideOut{movie=[Movie{id=2, name=Movie2, year=2008}], artist=[Artist{id=2, name='jane}]},
DivideOut{movie=[Movie{id=3, name=Movie3, year=1988}], artist=[Artist{id=1, name='jane}]},
DivideOut{movie=[Movie{id=3, name=Movie3, year=1988}], artist=[Artist{id=2, name='john}]}
]
Actual Output:
[
DivideOut{id=1, name=Movie1, year=2020, artist=[Artist{id=1, name='john}]},
DivideOut{id=1, name=Movie1, year=2020, artist=[Artist{id=2, name='jane}]},
DivideOut{id=2, name=Movie2, year=2008, artist=[Artist{id=1, name='john}]},
DivideOut{id=2, name=Movie2, year=2008, artist=[Artist{id=2, name='jane}]},
DivideOut{id=3, name=Movie3, year=1988, artist=[Artist{id=1, name='john}]},
DivideOut{id=3, name=Movie3, year=1988, artist=[Artist{id=2, name='jane}]}
]
Records of Movie is 3 and records of Artist is 2.
Artist and Movie records should be in separated lists, but they are mix.
Database is MSSQLSERVER 2016 and Driver JDBC.SQLServerDriver 11.2.0

Answer 1

The result map maps the query result to DivideOut object, so the first key question is "How many DivideOut instances do you expect?".
It seems that you just need two independent lists and don't care about DivideOut, so I assumed the answer is 1.
In the following statement, I added an extra query and named the result set dummy.
This extra query returns one row that creates the single DivideOut instance.
<select id="selectMultiple" resultSets="dummy,movies,artists"
resultMap="multipleQueriesResult" statementType="CALLABLE">
BEGIN
SELECT 1
END
BEGIN
SELECT
M.ID_ AS mId,
M.NAME_ AS mName,
M.YEAR_ AS mYear
FROM Movie AS M
END
BEGIN
SELECT A.ID_ AS aId,
A.NAME_ AS aName
FROM Artist AS A
END
</select>
If you just want two independent lists, it probably is better to 1) execute two independent SELECTs or 2) specify two result maps like this test.
Here is an executable demo:
https://github.com/harawata/mybatis-issues/tree/master/so-73685798