A Dangerous SQL

Look at this SQL, what's the problem?

<UpdateId="Update"ParameterType="Creativegroupdo">        UpdateDsp_creative_groupSetGmt_modified=Now ()<ifTest=The title!= NULL">, title=#{title,jdbctype=VARCHAR}        </if>        <ifTest="Clickurl!= NULL">, Click_url=#{clickurl,jdbctype=VARCHAR}        </if>        <where>            <ifTest="Creativegroupid!= NULL">                 andcreative_group_id=#{creativegroupid,jdbctype=BIGINT}            </if>        </where>    </Update>

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I don't seem to have a problem, but what if creativegroupid = null? All Dsp_creative_group records will be updated with the title, Clickurl to the same value, resulting in data loss.  You never know when the application will set the creative_group_id to NULL, which is almost uncontrollable. For online systems, once such a thing happens, it is definitely a disaster-level failure. The lesson is: Always, never add an if condition in the WHERE clause of the update!

A Dangerous SQL