I'm trying to produce a sql which is as below in mybatis.
SELECT COL_C
FROM TBLE_1
WHERE (COL_A, COL_B) in ( ('kp','kar'),('srt','sach'));
And my input parameter type is HashMap. Now How do I generate SQL from mapper xml file. The below code throws exception saying map evaluated to null.
<select id="selectCOLC" parameterType="java.util.HashMap" resultType="String">
SELECT COL_C
FROM TBLE_1
WHERE (COL_A, COL_B) in
<foreach item="item" collection="#{map.keySet()}" open="((" separator="),(" close="))">
#{item},#{item.get(item)}
</foreach>
</select>
One of the other approach is to create a class with key value fields, create a list of object and then pass the parameterType
as list
which would look like following.
<select id="selectCOLC" parameterType="list" resultType="String">
SELECT COL_C
FROM TBLE_1
WHERE (COL_A, COL_B) in
<foreach item="item" collection="list" open="((" separator="),(" close="))">
#{item.getKey()},#{item.getVal()}
</foreach>
</select>
But is there any way to my mapper work for the first approach? other than changing the query to union
This solution doesn't work since version 3.2 - see more in Issue #208 !
Finally I've the solution for HashMap
I Should use entrySet()
in order to make it iteratable
<select id="selectCOLC" parameterType="map" resultType="kpMap">
SELECT COL_C
FROM TBLE_1
WHERE (COL_A, COL_B) in
<foreach item="item" collection="entries.entrySet()" open="((" separator="),(" close="))">
#{item.key},#{item.value}
</foreach>
</select>
One more Isue I was facing parameter name was not getting injected, Hence added @Param
annotation
Hence mapper interface looks like below.
List<TblData> selectCOLC(@Param("entries")
HashMap<String, String> entries)