mybatis 为什么千万不要使用 where 1=1

<select id="findactivebloglike"
     resulttype="blog">
  select * from blog
  where
  <if test="state != null">
    state = #{state}
  </if>
  <if test="title != null">
    and title like #{title}
  </if>
  <if test="author != null and author.name != null">
    and author_name like #{author.name}
  </if>
</select>

select * from blog
where

select * from blog
where
and title like ‘sometitle'

<select id="findactivebloglike"
     resulttype="blog">
  select * from blog
  <where>
    <if test="state != null">
         state = #{state}
    </if>
    <if test="title != null">
        and title like #{title}
    </if>
    <if test="author != null and author.name != null">
        and author_name like #{author.name}
    </if>
  </where>
</select>