foreach 语句为数组或对象集合中的每个元素重复一个嵌入语句组。foreach 语句用于循环访问集合以获取所需信息，但不应用于更改集合内容以避免产生不可预知的副作用。
如果是一个带数据的List对象
<select id="selectProductMSTList" resultType="java.util.Map" parameterType="map">
SELECT
<foreach collection="fields" item="field" index="index" close="" separator=",">
#{field.tablekoumokuNames,jdbcType=VARCHAR}
</foreach>
FROM
${temp}.m_product
LEFT JOIN ${temp}.m_type_cd ON ${temp}.m_product.product_group_cd = ${temp}.m_type_cd.type_cd
WHERE
${temp}.m_product.anken_id = #{ankenId,jdbcType=VARCHAR} AND
${temp}.m_product.subsidiary_cd = #{subsidiaryCd,jdbcType=VARCHAR} AND
${temp}.m_product.sub_anken_id = #{subAnkenId,jdbcType=VARCHAR}
ORDER BY
${temp}.m_product.subsidiary_cd ASC,
${temp}.m_product.brand_cd ASC,
${temp}.m_product.product_cd ASC
</select>
遍历一个map对象：
Map<String,Object> xx=new HashMap<String, Object>();
xx.put("22","ABC");
paramMap.put("maps",xx);
<foreach collection="maps" item="field" index="key" separator=",">
${field}={key}
</foreach>
