<trim prefix="where" prefixOverrides="and"> p.delete_flag = 0 and p.profession = '管理人员' <if test="param.personName != null and param.personName != '' ">

</if> <if test="param.personAge != null">and p.age = #{param.personAge}</if> <if test="param.personGender != null and param.personGender != ''">and p.gender = #{param.personGender}</if> </trim>

请问这段代码是用来做什么的？