mybatis return result map with duplicate entry - mybatis

Question

I am using mybatis to retrieve data from DB, the data returned is containing duplicate entries.
Required result : Column Name , Value
Expected result is : column1 value A
But returned result is : COLUMN1 value A , column1 value A.
Hope able to clarify my doubt.
Can anybody tell me why it is happening?
<select id="getContentMap" resultType="map" parameterType="map">
select planId,location_qualifier from disclaimer_disclosure_content where
<choose>
<when test="plan_id != null">
plan_id = #{plan_id}
</when>
<when test="product_id != null">
product_id = #{product_id}
</when>
<otherwise>
issuer_id = #{issuer_id}
</otherwise>
</choose>
and effective_date >= #{effective_date}
and location_qualifier LIKE CONCAT('%' , #{location_qualifier} , '%')
</select>

Answer 1

The issue you are seeing is a bug in MyBatis 3 up until release 3.0.6: http://code.google.com/p/mybatis/issues/detail?id=303.
After that release you get the answer I outlined in my other answer (which was done with MyBatis 3.1.1).
You have four options:
Just ignore it and only grab the uppercase or lowercase entries
Upgrade to at least 3.0.6
Stop using map as resultType and move to a POJO domain object
Use the workaround below:
workaround for MyBatis < 3.0.6
Use full uppercase column aliases and they will only show up once (as uppercase) in your map:
<select id="getContentMap" resultType="map" parameterType="map">
select plan_id as PLAN_ID, location_qualifier as LOCATION_QUALIFIER from disclaimer_disclosure_content
where
<!-- SNIP: is the same as you had -->
</select>
This results in the output:
{PLAN_ID=2, LOCATION_QUALIFIER=Bar}
(or something similar depending on exactly how your select looks).

Answer 2

You will probably need to report more information, such as:
what database are you using?
what version of MyBatis 3 are you using (or are you still using iBATIS)?
what does your table structure look like?
In any case, I tried out a slightly simplified version of your query using MySQL 5.1 and MyBatis-3.1.1 and it worked fine - meaning that I only got back one entry of the column name in the result map. I provide my setup below so you can try to reproduce it or diagnose where your code may be wrong.
First, you have a error in your select statement. You have
SELECT planId
but then you have:
WHERE ... plan_id = #{plan_id}
so you probably meant SELECT plan_id in the SELECT clause.
Here is what worked for me.
My slightly simplified MyBatis select mapping is:
<select id="getContentMap" resultType="map" parameterType="map">
SELECT plan_id, location_qualifier FROM disclaimer_disclosure_content
WHERE
<choose>
<when test="plan_id != null">
plan_id = #{plan_id}
</when>
<otherwise>
product_id = #{product_id}
</otherwise>
</choose>
AND location_qualifier LIKE CONCAT('%' , #{location_qualifier} , '%')
</select>
Second, my MySQL table for this query:
mysql> select * from disclaimer_disclosure_content;
+---------+--------------------+------------+
| plan_id | location_qualifier | product_id |
+---------+--------------------+------------+
| 1 | Foo | 101 |
| 2 | Bar | 102 |
| 3 | Baz | 103 |
| 4 | Quux | 104 |
+---------+--------------------+------------+
4 rows in set (0.01 sec)
Third, my Java code to use the mapping:
#Test
public void testForSO() throws Exception {
Map<String, Object> paramMap = new HashMap<String, Object>();
paramMap.put("plan_id", 2);
paramMap.put("location_qualifier", "Ba");
List<Map<String,Object>> lmap = session.selectList("getContentMap", paramMap);
assertNotNull(lmap);
Map<String,Object> m = lmap.get(0);
assertNotNull(m);
System.out.println(m.toString());
}
This passes and prints out:
{location_qualifier=Bar, plan_id=2}
I also tried it with
Map<String,Object> m = session.selectOne("getContentMap", paramMap);
and get the same expected result.