其中通过"%"#{key}"%"来拼接语句
<sql id="select_where">
from cellphone c left join client cl on c.client=cl.id left join
client cli on c.receiver=cli.id
<if test="key!=null">
where phone_brand like "%"#{key}"%" or phone_model like
"%"#{key}"%" or IMEI like
"%"#{key}"%"
</if>
order by id desc limit #{pageIndex},#{pageSize}
</sql>