如果在 phpmyadmin 触发器中不工作

Question

所以我在 phpmyadmin 中使用 MySQL 触发器。这是我对表 scorm_track 的触发器：

UPDATE userbatch 
LEFT JOIN scorm_track 
ON      
        (userbatch.user_id = scorm_track.userid)
LEFT JOIN trainingobject
ON      
        (scorm_track.tobjid = trainingobject.id)
IF scorm_track.element = 'cmi.core.lesson_status' THEN
    SET userbatch.to_completion = scorm_track.value,
        userbatch.trainingcompleted = scorm_track.timemodified;
ELSEIF scorm_track.element = 'cmi.core.score.raw' THEN
    SET userbatch.comment = scorm_track.value;
ENDIF;
WHERE (userbatch.batch_id = trainingobject.batchid) AND 
        scorm_track.id=NEW.id AND 
        scorm_track.element = 'cmi.core.lesson_status' OR scorm_track.element = 'cmi.core.score.raw'

但它显示以下错误：“MySQL 说 #1064 - You have an error in your SQL syntax...”

这个问题是在我添加了 IF ELSE 语句后开始出现的。它以前工作正常。谁能说明为什么会发生这种情况？

Answer 1

这是因为加入时更新语法错误。 if-else 的用法在这里是错误的。查询应该是

update userbatch ub
left join scorm_track st on ub.user_id = st.userid
left join trainingobject tob on tob.id = st.tobjid
set
ub.to_completion = 
 case 
   when st.element = 'cmi.core.lesson_status' then st.value 
 end ,
ub.to_completion = 
 case when st.element = 'cmi.core.lesson_status' then st.value 
end, 
ub.trainingcompleted = 
 case when st.element = 'cmi.core.lesson_status' then st.timemodified 
end, 
ub.comment = 
case when st.element = 'cmi.core.score.raw' then st.value 
end
where 
ub.batch_id = tob.batchid
and st.id = new.id 
and ( st.element = 'cmi.core.lesson_status' or st.element = 'cmi.core.score.raw )