mybatis ordering by many fields with dynamic sql - ibatis

Question

Is there a cleaner way of doing the next :
<select id="getWithQueryData" resultMap="usuarioResult" parameterType="my.QueryData" >
select * from t_user
<if test="fieldName != null and ascDesc != null">
order by
<choose>
<when test="fieldName == 'name'">
c_name
</when>
<when test="fieldName == 'lastName'">
c_last_name
</when>
<when test="fieldName == 'email'">
c_email
</when>
<when test="fieldName == 'password'">
c_password
</when>
<when test="fieldName == 'age'">
i_age
</when>
</choose>
<if test="ascDesc == 'asc'">
asc
</if>
<if test="ascDesc == 'desc'">
desc
</if>
</if>
limit #{limit} offset #{offset};
As you could infer, QueryData looks like:
public class FiltroBusquedaVO {
private Integer offset;
private Integer limit;
private String fieldName;
private String ascDesc; ... }
Would be nice if I could get a column name given a fieldName. I mean, the result maps have that info. But it seems I can not get it from the xml.
My example has just 5 fields, but what about 20 fields? Is there another way around of doing this less verbose?

Answer 1

See my answer on a similar problem.
Mybatis map property to column
But with that the only downside is you java code will know about the column names.

Answer 2

This is how I did it:
List<ProjectLockDBO> getProjectsLocks(#Param("projectId") Integer projectId, #Param("userId") Integer userId, #Param("limit") Integer limit,
#Param("offset") Integer offset, #Param("sortAsc") List<String> sortAsc, #Param("sortDesc") List<String> sortDesc);
<select id="getProjectsLocks" resultMap="ProjectLockResult">
SELECT pl.id,
pl.project_id,
pl.notes,
pl.created_by_id,
pl.created_at,
u.id AS user_id,
u.email AS user_email,
u.first_name AS user_first_name,
u.last_name AS user_last_name
FROM projects_locks pl
LEFT JOIN users u ON u.id = pl.created_by_id
WHERE 1=1
<if test="projectId != null"> AND pl.project_id = #{projectId}</if>
<if test="userId != null"> AND pl.created_by_id = #{userId}</if>
<choose>
<when test="sortAsc != null or sortDesc != null">
ORDER BY <if test="sortAsc != null">
<foreach collection="sortAsc" item="element" open="" close=" ASC" separator=",">
${element}
</foreach>
</if>
<if test="sortAsc != null and sortDesc != null">, </if>
<if test="sortDesc != null">
<foreach collection="sortDesc" item="element" open="" close=" DESC" separator=",">
${element}
</foreach>
</if>
</when>
<otherwise>ORDER BY pl.id;</otherwise>
</choose>
<if test="limit != null">LIMIT #{limit}</if>
<if test="offset != null">OFFSET #{offset}</if>
</select>
Where the 2 lists will contain strings like: "pl.project_id", "pl.id",
The critical part here is the dollar sign "$" in front of the {element}. If you will use the standard #, it won't work.