join

Slow self-join delete query

由 笑着哭i 提交于 2020-02-25 09:42:11
问题 Does it get any simpler than this query? delete a.* from matches a inner join matches b ON (a.uid = b.matcheduid) Yes, apparently it does... because the performance on the above query is really bad when the matches table is very large. matches is about 220 million records. I am hoping that this DELETE query takes the size down to about 15,000 records. How can I improve the performance of the query? I have indexes on both columns. UID and MatchedUID are the only two columns in this InnoDB

Slow self-join delete query

由 六眼飞鱼酱① 提交于 2020-02-25 09:42:03
问题 Does it get any simpler than this query? delete a.* from matches a inner join matches b ON (a.uid = b.matcheduid) Yes, apparently it does... because the performance on the above query is really bad when the matches table is very large. matches is about 220 million records. I am hoping that this DELETE query takes the size down to about 15,000 records. How can I improve the performance of the query? I have indexes on both columns. UID and MatchedUID are the only two columns in this InnoDB

Slow self-join delete query

由 梦想的初衷 提交于 2020-02-25 09:41:57
问题 Does it get any simpler than this query? delete a.* from matches a inner join matches b ON (a.uid = b.matcheduid) Yes, apparently it does... because the performance on the above query is really bad when the matches table is very large. matches is about 220 million records. I am hoping that this DELETE query takes the size down to about 15,000 records. How can I improve the performance of the query? I have indexes on both columns. UID and MatchedUID are the only two columns in this InnoDB

What index should I use when using JOIN on PRIMARY KEY

由 ぐ巨炮叔叔 提交于 2020-02-25 04:16:59
问题 I'm trying to optimise the following MySQL query SELECT Hotel.HotelId, Hotel.Name, Hotel.Enabled, Hotel.IsClosed, HotelRoom.HotelId, HotelRoom.RoomId, HotelRoom.Name AS RoomName FROM Hotel INNER JOIN HotelRoom ON Hotel.HotelId = HotelRoom.HotelId WHERE Hotel.IsClosed = 0 AND Hotel.Enabled = 1 AND HotelRoom.Deleted = 0 AND HotelRoom.Enabled = 1 AND IF(LENGTH(TRIM(sAuxiliaryIds)) > 0 AND sAuxiliaryIds IS NOT NULL, FIND_IN_SET(Hotel.AuxiliaryId, sAuxiliaryIds), 1=1) > 0 ORDER BY Hotel.HotelId

How to use Pandas in apache beam?

由 痴心易碎 提交于 2020-02-24 10:16:49
问题 How to implement Pandas in Apache beam ? I cannot perform left join on multiple columns and Pcollections does not support sql queries. Even the Apache Beam document is not properly framed. I checked but couldn't find any kind of Panda implementation in Apache beam. Can anyone direct me to the desired link ? 回答1: There's some confusion going on here. pandas is "supported", in the sense that you can use the pandas library the same way you'd be using it without Apache Beam, and the same way you

Can't get result from $this->db->last_query(); codeigniter

由 邮差的信 提交于 2020-02-24 05:12:04
问题 Quite a simple thing to ask and must be discussed many times, but I still not able to get the result of $this->db->last_query();. $this->db->select('count(*) as totalverified,res_sales.upduser, employee.name'); $this->db->from('res_sales'); $this->db->join('employee','employee.user_id = res_sales.upduser'); $this->db->where('date>=', $fromdate); $this->db->where('date<=', $todate); $this->db->where('verificationnumber<>', ''); $this->db->where('verificationnumber<>', NULL); $this->db->group

Include with FromSqlRaw and stored procedure in EF Core 3.1

由 百般思念 提交于 2020-02-23 10:40:30
问题 So here's the deal - I am currently using EF Core 3.1 and let's say I have an entity: public class Entity { public int Id { get; set; } public int AnotherEntityId { get; set; } public virtual AnotherEntity AnotherEntity { get; set; } } When I access the DbSet<Entity> Entities normal way, I include AnotherEntity like: _context.Entities.Include(e => e.AnotherEntity) and this works. Why wouldn't it, right? Then I go with: _context.Entities.FromSqlRaw("SELECT * FROM Entities").Include(e => e

Join on data from XML in T-SQL

由 删除回忆录丶 提交于 2020-02-23 09:47:48
问题 I have the following XML message: DECLARE @XML AS XML SET @XML = '<Message> <Changes> <Deleted> <ROW id="1" name="Nicole" surname="Bartlett" city="denver" balance="779.4663" dateOfBirth="1991-12-11T14:05:42.830" maritalStatus="S" /> <ROW id="1" name="Nicole" surname="Bartlett" city="boston" balance="779.4663" dateOfBirth="1991-12-11T14:05:42.830" maritalStatus="S" /> </Deleted> <Inserted> <ROW id="1" name="Nicole" surname="Bartlett" city="denver" balance="779.4663" dateOfBirth="1991-12-11T14

mySQL count occurrences with JOIN

由 五迷三道 提交于 2020-02-23 08:08:20
问题 I have a tagging system for my events system I would like to create a 'tag cloud'. I have Events, which can have multiple 'categories'. Here's the table structure: **Event_Categories** (Stores Tags / Categories) | id | name | +-----------------+ + 1 | sport | + 2 | charity | + 3 | other_tag | **Events_Categories** (Linking Table) | event_id | event_category_id | +-------------------------------+ + 1 | 1 | + 2 | 2 | + 3 | 1 | + 3 | 2 | Summary: Event ID 1 -> Sport Event ID 2 -> Charity Event

并查集的python实现

由 依然范特西╮ 提交于 2020-02-22 15:50:08
import numpy as np import os class DIS_JOIN(object): def __init__(self): ''' 并查集算法 拥有两个函数 一个是把某个元素放在某个集合中 另一个是返回一个list，包含所有集合和集合中所有的点 ''' self.Set = None self.Sum = None self.n = None def clear(self, n): ''' 初始化 n为一共有多少个元素 ''' self.Set = np.zeros(n, dtype=int) self.Set = self.Set - 1 # 都初始化为-1. 表示他自己就是根. Set是一个数组. # Set[i] 表示i的根是谁. self.Sum = n self.n = n return def find_r(self, p): ''' 返回p属于那一个集合 ''' if self.Set[p] < 0: return p self.Set[p] = self.find_r(self.Set[p]) #通过迭代不停的找根. return self.Set[p] def join(self, a, b): ''' 将元素b加入元素a所在的集合中 ''' ra = self.find_r(a) rb = self.find_r(b) if (ra !=
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