mybatis update语句判断怎么写？

<!-- 修改 -->
		<update id="updateWorkJobs" parameterType="com.lvic.prsp.dao.dto.CRM_JobsDto"> 
			UPDATE PRSP_CRM_ENTERPRISE 
			<trim prefix="SET" suffixOverrides=",">
			    	<if test="null != enterp_name and '' != enterp_name">
			           ENTERP_NAME=#{enterp_name,jdbcType=VARCHAR},
			       </if>
			   		<if test="null != enterp_type and '' != enterp_type">
			            ENTERP_TYPE=#{enterp_type,jdbcType=VARCHAR},
			       </if>
			        <if test="null != enterp_address and '' != enterp_address">
			             ENTERP_ADDRESS=#{enterp_address,jdbcType=VARCHAR},
			       </if>
			        <if test="null != enterp_resume and '' != enterp_resume">
			            ENTERP_RESUME=#{enterp_resume,jdbcType=VARCHAR},
			       </if>
			   </trim>
			      ,UPDATETIMESTAMP=sysdate
			WHERE ENTERP_NO=#{enterp_no,jdbcType=INTEGER} 
			  AND DELETE_FLG='0'
		</update>