Question

我在MySQL中有以下查询：

SELECT query.*,
  GROUP_CONCAT(COALESCE(query.gene,'None'), '(', query.loc, '|', COALESCE(query.typ,'unknown'), ')') AS outt
FROM (
  SELECT genes.loc,
  genes.typ, genes.abans, genes.despres, genes.gene, 
  mutations.id,mutations.chr,mutations.pos,mutations.ref,
  mutations.ale,mutations.g001,mutations.g002,mutations.g003,
  .... (snipped hundreds of denormalized fields)....
  FROM genes
  INNER JOIN mutations
  ON genes.id=mutations.id
  WHERE (mutations.g001>=0.40 
    AND mutations.g002>=0.40 AND mutations.g003>=0.40 
    AND mutations.g004>=0.40 AND mutations.g005>=0.40 
    AND mutations.g006>=0.40 AND mutations.g007>=0.40 
    AND mutations.g008>=0.40 AND mutations.g011>=0.40  
    AND mutations.g012>=0.40 AND mutations.g013>=0.40  
    AND mutations.g014>=0.40 AND mutations.g015>=0.40  
    AND ....(you get the idea)...
    AND mutations.g105>=0.40
  ) LIMIT 0, 100
) AS query 
GROUP BY query.id

我在该查询中执行GROUP_CONCAT并且它运行良好。问题是我想要100行，而由于GROUP BY，我得到的行少于100行。尝试将GROUP_CONCAT直接应用于内部查询时，速度非常慢。你有什么建议吗？

GROUP_CONCAT在MySQL中很慢

0 个答案: