IBATIS中的include功能

<sql id="selectItem_fragment">
    FROM items
    WHERE parentid = 6
</sql>
<select id="selectItemCount" resultClass="int">
    SELECT COUNT(*) AS total
    <include refid="selectItem_fragment"/>
</select>
<select id="selectItems" resultClass="Item">
    SELECT id, name
    <include refid="selectItem_fragment"/>
</select>