select score from (
SELECT *, @rownum:=@rownum+1 AS seq
FROM EXT_THREAT_GUIDE
WHERE high_id='1' AND low_id='18' AND(@rownum:=0)=0
) A WHERE seq = '1';
SELECT score FROM (
SELECT *
, ROW_NUMBER() OVER(ORDER BY score DESC) AS seq
FROM EXT_THREAT_GUIDE
WHERE high_id = #{high_id} AND low_id= #{low_id}
) A
WHERE seq = #{freq_score}