mysql : 需要缩短查询

Posted 2023-02-24

【中文标题】mysql : 需要缩短查询

【英文标题】：mysql : Need to short a query

【发布时间】：2013-06-12 10:30:59

【问题描述】：

我有查询，它给出了正确的结果，但是，它有内部查询，重复相同的条件。我已经尽量缩短查询的长度。

谁能帮我降低查询的复杂性，因为它需要 12 分钟才能在服务器中获得结果，这可能会在未来引起很多问题。

问题是，重复相同的条件，并且查询在其中使用内部查询。

使用这些mysql参数查询：-

sum,if,GROUP_CONCAT。

查询：-

select 
sum( 
IF(priority="P1",1,0)) P1,
sum( 
IF((timediff(delta_ts,creation_ts) > "00:02:00") 
 && (priority="P1") ,1,0))P1_exeeded,
 (select 
 GROUP_CONCAT( DISTINCT bug_id) 
 from bugs 
 where  
 ( 
   IF((timediff(delta_ts,creation_ts) > "00:02:00") && (priority="P1") 
   && (product_id=237)
   &&(bugs.resolution='FIXED')
   &&(bug_status="RESOLVED")
   &&(bugs.creation_ts >='2013-06-14 09:00:00' 
   && bugs.creation_ts <= '2013-06-16 08:59:59') ,1,0)
 )
) as bug_ids,

SUM(
IF(priority="P2",1,0)) P2,
sum( 
IF((timediff(delta_ts,creation_ts) > "00:01:00") 
&& (priority="P2") ,1,0))P2_exeeded,
(select GROUP_CONCAT( DISTINCT bug_id) 
 from bugs 
 where
 ( 
 IF((timediff(delta_ts,creation_ts) > "00:02:00") 
 && (priority="P2") 
 && (product_id=237)&&(bugs.resolution='FIXED')
 &&(bug_status="RESOLVED")&&(bugs.creation_ts >='2013-06-14 09:00:00' 
 && bugs.creation_ts <= '2013-06-16 08:59:59') ,1,0)
 )
 ) as bug_ids,
 SUM(
 IF(priority="P3",1,0)) P3count,
 SUM(
 IF(priority="P4",1,0)) P4count 
 from bugs 
 where bugs.product_id=237 
 and bugs.resolution='FIXED' 
 and bugs.creation_ts >='2013-06-14 09:00:00' 
 and bugs.creation_ts <= '2013-06-16 08:59:59' 
 and bug_status="RESOLVED";

结果：-

+--------+------------+---------+------+------------ +---------+---------+---------+ | P1 | P1_exeeded | bug_ids | P2 | P2_exeeded | bug_ids | P3count | P4count | +--------+------------+---------+------+------------ +---------+---------+---------+ | 7 | 1 | 3743304 | 6 | 1 | 3743305 | 5 | 1 | +--------+------------+---------+------+------------ +---------+---------+---------+ 为了获取错误 ID，我使用了 group concat。查询变得复杂

【问题讨论】：

索引也是你的朋友，如果你发现自己在 where 条件中使用了很多列，创建一个索引，你会看到神奇的事情发生；)

同意你必须正确索引表格

谁能举个简单的例子吗？

如前所述，添加一个索引，涵盖 where 或 order by 语句中使用的所有字段。您的索引可能会有所不同，具体取决于您的数据库引擎，但通常这应该会提高性能。请注意，索引会增加您的数据库大小，特别是如果您添加许多索引，大型数据库可能会变得更大！

【参考方案1】：

得到答案：-

像这样解决它：-

select 
sum(
IF(
priority="P1",1,0)) P1, 
sum(
IF(
(timediff(delta_ts,creation_ts) > "00:02:00") && (priority="P1") ,1,0)) P1_exeeded,
REPLACE(GROUP_CONCAT(
IF(
(timediff(delta_ts,creation_ts) > "00:02:00") 
  && (priority="P1") ,bug_id,'')),',,','' ) as bugids,  
SUM(
IF(priority="P2",1,0)) P2, 
sum( IF((timediff(delta_ts,creation_ts) > "00:01:00") 
 && (priority="P2") ,1,0))P2_exeeded,
REPLACE(GROUP_CONCAT(IF((timediff(delta_ts,creation_ts) > "00:02:00") 
 && (priority="P2") ,bug_id,'')),',,','' ) as bugids ,
SUM(
IF(priority="P3",1,0)) P3count, 
sum( 
IF(
(timediff(delta_ts,creation_ts) > "00:02:00") 
&& (priority="P3"),1,0))P3_exeeded,
REPLACE(GROUP_CONCAT(
IF((timediff(delta_ts,creation_ts) > "00:02:00") 
 && (priority="P3") ,bug_id,'')),',,','' ) asbugids, 
SUM(
 IF(priority="P4",1,0)) P4count,
sum(
 IF(
(timediff(delta_ts,creation_ts) > "00:02:00") 
 && (priority="P4") ,1,0)) P4_exeeded,
 REPLACE(
 GROUP_CONCAT(
  IF(
  (timediff(delta_ts,creation_ts) > "00:02:00") 
  && (priority="P4") ,bug_id,'')),',,','' ) as bugids 
  from bugs 
  where bugs.product_id=237 
  and bugs.resolution  ='FIXED' 
  and bugs.creation_ts >='2013-06-14 09:00:00' 
  and bugs.creation_ts <= '2013-06-16 08:59:59' 
  and bug_status="RESOLVED";

我在 0.01 秒

内得到了结果 +--------+------------+------------+------+---------- --+---------+---------+------------+--------+----- ----+------------+--------+ | P1 | P1_exeeded |臭虫 | P2 | P2_exeeded |臭虫 | P3count | P3_exeeded |臭虫 | P4count | P4_exeeded |臭虫 | +--------+------------+------------+------+---------- --+---------+---------+------------+--------+----- ----+------------+--------+ | 7 | 1 | ,3743304, | 6 | 1 | 3743305 | 5 | 0 | | 1 | 0 | | +--------+------------+------------+------+---------- --+---------+---------+------------+--------+-- ----+------------+--------+

谢谢大家，我使用了替换，而不是内部查询，并使用了 group con cat，没有内部查询。