oracle
<insert id="addUserData" parameterType="java.util.List">
INSERT INTO T_P_USER_DATA (USER_ID, DEPART_ID)
<foreach collection="list" item="item" index="index" separator=" UNION ALL ">
SELECT #{item.userId}, #{item.departId} FROM DUAL
</foreach>
</insert>
mysql
<insert id="addUserData" parameterType="java.util.List">
INSERT INTO T_P_USER_DATA (USER_ID, DEPART_ID)
VALUES <foreach collection="list" item="item" index="index"
separator=",">
( #{item.userId}, #{item.departId})
</foreach>
</insert>