使用到group_concat 查询时间慢,不知道怎么优化
SELECT ansg.qa_id AS ans_id,GROUP_CONCAT(con.context) as content
FROM core_answer ansg
INNER JOIN core_context con
ON ansg.content_id=con.id
AND ansg.is_shared='0'
GROUP BY ansg.qa_id
加 EXPLAIN 之后
EXPLAIN SELECT ansg.qa_id AS ans_id,GROUP_CONCAT(con.context) as content
FROM core_answer ansg
INNER JOIN core_context con
ON ansg.content_id=con.id
AND ansg.is_shared='0'
GROUP BY ansg.qa_id
