MySQL5.7對sql語句強制使用索引查詢時報錯如下：
解決：這里的id字段是表的主鍵，查看別人的經驗貼得知是語法錯誤，參考鏈接https://stackoverflow.com/questions/19205004/key-emp-no-doesnt-exist-in-table-employees ，當強制索引是主鍵時sql語句應這樣寫
mysql> SELECT COUNT(UA.id) AS tp_count FROM ck_user_audit UA RIGHT JOIN ck_user AS U force index(PRIMARY) ON U.id = UA.uid LIMIT 1;