MyBatis string comparison

Information was diverged in the description of dynamic SQL in xml using MyBatis, so I am checking what to do actually Can I use single quotes?

There was a report that other members confirmed it and it was useless. .. .. I could not confirm what kind of Exception occurred. .. .. Although it is a char type once, it can only be entered as a business specification, so it is cleared without single quotation Will be confirmed when needed again

　　 <!--Exception occurred-->
    select * from table
    <if test="args != '9'">
        where colum = #{args}
    </if> 

　　 <!--Correspondence once-->
    select * from table
    <if test="args != 9">
        where colum = #{args}
    </if>