Mybaits中的update

<update id="update" parameterType="Currency">
        UPDATE 
            YZ_SECURITIES_CURRENCY
        <trim prefix="SET" prefixOverrides=",">
            <if test="folwType != null and flowType != ''"> ,FLOW_TYPE = #{flowType}</if>
            <if test="title != null and title != ''"> , TITLE = #{title}</if>
            <if test="applyUserName != null and applyUserName != ''"> , APPLY_USER_NAME = #{applyUserName}</if>
            <if test="applyDate != null and applyDate != ''"> , APPLY_DATE = #{applyDate}</if>
            <if test="applyUserDept != null and applyUserDept != ''"> , APPLY_USER_DEPT = #{applyUserDept}</if>
            <if test="applyContent != null and applyContent !=''">, APPLY_CONTENT = #{applyContent}</if>
            <if test="contactUser != null and contactUser != ''"> , CONTACT_USER = #{contactUser}</if>
            <if test="contactPhone != null and contactPhone !=''"> , CONTACT_PHONE = #{contactPhone}</if>
            <if test="zhubDept != null and zhubDept != ''"> , ZHUB_DEPT = #{zhubDept}</if>
            <if test="proceedingExplanation != null and proceedingExplanation != ''"> , PROCEEDING_EXPLANATION = #{proceedingExplanation}</if>
            <if test="memo != null and memo != ''"> , MEMO = #{memo}</if>
            <if test="overDate != null and overDate != ''">,OVER_DATE = #{overDate}</if>
            <if test="orgId != null and orgId != ''"> , ORG_ID = #{orgId}</if>
            <if test="creUnit != null and creUnit != ''"> , CRE_UNIT = #{creUnit}</if>
            <if test="creUserId != null and creUserId != ''"> , CRE_USER_ID = #{creUserId}</if>
            <if test="creDeptId != null and creDeptId != ''"> , CRE_DEPT_ID = #{creDeptId}</if>
            <if test="subflag != null and subflag != ''"> , SUBFLAG = #{subflag}</if>
        </trim>
        WHERE
            ID = #{id}
    </update>