將某個值從TableA複製到TableB的特定條件下

update friend_help SET thought = (select choice.choice_name  FROM choice WHERE choice.iscorrect = '1' AND choice.question_id = friend_help.question_id)
WHERE friend_help.thought like '%這個題目類別%' AND (select question.category_id FROM question WHERE question.question_id = friend_help.question_id)<10

將TableA的甲欄位複製到TableB的甲欄位

Insert into question_group (question_id) select question.question_id from question

將Btable限制1筆對應到Atable

UPDATE question set question.category_sub_id = (SELECT category_sub.category_sub_id FROM category_sub WHERE category_sub.category_id = question.category_id LIMIT 1)