/
join_cache.result
6258 lines (6252 loc) · 223 KB
/
join_cache.result
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DROP TABLE IF EXISTS t1,t2,t3,t4,t5,t6,t7,t8,t9,t10,t11;
DROP DATABASE IF EXISTS world;
set @org_optimizer_switch=@@optimizer_switch;
set @save_join_cache_level=@@join_cache_level;
set @save_join_buffer_space_limit=@@join_buffer_space_limit;
set @save_join_buffer_size=@@join_buffer_size;
set @save_expensive_subquery_limit=@@expensive_subquery_limit;
set @@optimizer_switch='optimize_join_buffer_size=on';
set @@optimizer_switch='semijoin=on,firstmatch=on,loosescan=on';
set @@optimizer_switch='semijoin_with_cache=on';
set @@optimizer_switch='outer_join_with_cache=on';
set @@optimizer_switch='mrr=on,mrr_sort_keys=on,index_condition_pushdown=on';
set @local_optimizer_switch=@@optimizer_switch;
set @innodb_stats_persistent_save= @@innodb_stats_persistent;
set @innodb_stats_persistent_sample_pages_save=
@@innodb_stats_persistent_sample_pages;
set global innodb_stats_persistent= 1;
set global innodb_stats_persistent_sample_pages=100;
set names utf8;
CREATE DATABASE world;
use world;
CREATE TABLE Country (
Code char(3) NOT NULL default '',
Name char(52) NOT NULL default '',
SurfaceArea float(10,2) NOT NULL default '0.00',
Population int(11) NOT NULL default '0',
Capital int(11) default NULL
);
CREATE TABLE City (
ID int(11) NOT NULL,
Name char(35) NOT NULL default '',
Country char(3) NOT NULL default '',
Population int(11) NOT NULL default '0'
);
CREATE TABLE CountryLanguage (
Country char(3) NOT NULL default '',
Language char(30) NOT NULL default '',
Percentage float(3,1) NOT NULL default '0.0'
);
SELECT COUNT(*) FROM Country;
COUNT(*)
239
SELECT COUNT(*) FROM City;
COUNT(*)
4079
SELECT COUNT(*) FROM CountryLanguage;
COUNT(*)
984
show variables like 'join_buffer_size';
Variable_name Value
join_buffer_size 262144
set join_cache_level=1;
show variables like 'join_cache_level';
Variable_name Value
join_cache_level 1
EXPLAIN
SELECT City.Name, Country.Name FROM City,Country
WHERE City.Country=Country.Code AND
Country.Name LIKE 'L%' AND City.Population > 100000;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE Country ALL NULL NULL NULL NULL 239 Using where
1 SIMPLE City ALL NULL NULL NULL NULL 4079 Using where; Using join buffer (flat, BNL join)
SELECT City.Name, Country.Name FROM City,Country
WHERE City.Country=Country.Code AND
Country.Name LIKE 'L%' AND City.Population > 100000;
Name Name
?iauliai Lithuania
Beirut Lebanon
Bengasi Libyan Arab Jamahiriya
Daugavpils Latvia
Kaunas Lithuania
Klaipeda Lithuania
Maseru Lesotho
Misrata Libyan Arab Jamahiriya
Monrovia Liberia
Panevezys Lithuania
Riga Latvia
Tripoli Lebanon
Tripoli Libyan Arab Jamahiriya
Vientiane Laos
Vilnius Lithuania
EXPLAIN
SELECT City.Name, Country.Name, CountryLanguage.Language
FROM City,Country,CountryLanguage
WHERE City.Country=Country.Code AND
CountryLanguage.Country=Country.Code AND
City.Name LIKE 'L%' AND Country.Population > 3000000 AND
CountryLanguage.Percentage > 50 AND
LENGTH(Language) < LENGTH(City.Name) - 2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE Country ALL NULL NULL NULL NULL 239 Using where
1 SIMPLE CountryLanguage ALL NULL NULL NULL NULL 984 Using where; Using join buffer (flat, BNL join)
1 SIMPLE City ALL NULL NULL NULL NULL 4079 Using where; Using join buffer (flat, BNL join)
SELECT City.Name, Country.Name, CountryLanguage.Language
FROM City,Country,CountryLanguage
WHERE City.Country=Country.Code AND
CountryLanguage.Country=Country.Code AND
City.Name LIKE 'L%' AND Country.Population > 3000000 AND
CountryLanguage.Percentage > 50 AND
LENGTH(Language) < LENGTH(City.Name) - 2;
Name Name Language
La Matanza Argentina Spanish
Lagos de Moreno Mexico Spanish
Lalitapur Nepal Nepali
Las Margaritas Mexico Spanish
Las Palmas de Gran Canaria Spain Spanish
Lashio (Lasho) Myanmar Burmese
Lauro de Freitas Brazil Portuguese
Lengshuijiang China Chinese
Leninsk-Kuznetski Russian Federation Russian
Leverkusen Germany German
Lexington-Fayette United States English
Liangcheng China Chinese
Lianyungang China Chinese
Little Rock United States English
Liupanshui China Chinese
Lleida (Lérida) Spain Spanish
Lomas de Zamora Argentina Spanish
Long Beach United States English
Los Angeles Chile Spanish
Los Angeles United States English
Los Teques Venezuela Spanish
Louisville United States English
Lower Hutt New Zealand English
Luchou Taiwan Min
Ludwigshafen am Rhein Germany German
Lungtan Taiwan Min
L´Hospitalet de Llobregat Spain Spanish
Lázaro Cárdenas Mexico Spanish
set join_cache_level=2;
show variables like 'join_cache_level';
Variable_name Value
join_cache_level 2
EXPLAIN
SELECT City.Name, Country.Name FROM City,Country
WHERE City.Country=Country.Code AND
Country.Name LIKE 'L%' AND City.Population > 100000;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE Country ALL NULL NULL NULL NULL 239 Using where
1 SIMPLE City ALL NULL NULL NULL NULL 4079 Using where; Using join buffer (flat, BNL join)
SELECT City.Name, Country.Name FROM City,Country
WHERE City.Country=Country.Code AND
Country.Name LIKE 'L%' AND City.Population > 100000;
Name Name
?iauliai Lithuania
Beirut Lebanon
Bengasi Libyan Arab Jamahiriya
Daugavpils Latvia
Kaunas Lithuania
Klaipeda Lithuania
Maseru Lesotho
Misrata Libyan Arab Jamahiriya
Monrovia Liberia
Panevezys Lithuania
Riga Latvia
Tripoli Lebanon
Tripoli Libyan Arab Jamahiriya
Vientiane Laos
Vilnius Lithuania
EXPLAIN
SELECT City.Name, Country.Name, CountryLanguage.Language
FROM City,Country,CountryLanguage
WHERE City.Country=Country.Code AND
CountryLanguage.Country=Country.Code AND
City.Name LIKE 'L%' AND Country.Population > 3000000 AND
CountryLanguage.Percentage > 50 AND
LENGTH(Language) < LENGTH(City.Name) - 2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE Country ALL NULL NULL NULL NULL 239 Using where
1 SIMPLE CountryLanguage ALL NULL NULL NULL NULL 984 Using where; Using join buffer (flat, BNL join)
1 SIMPLE City ALL NULL NULL NULL NULL 4079 Using where; Using join buffer (incremental, BNL join)
SELECT City.Name, Country.Name, CountryLanguage.Language
FROM City,Country,CountryLanguage
WHERE City.Country=Country.Code AND
CountryLanguage.Country=Country.Code AND
City.Name LIKE 'L%' AND Country.Population > 3000000 AND
CountryLanguage.Percentage > 50 AND
LENGTH(Language) < LENGTH(City.Name) - 2;
Name Name Language
La Matanza Argentina Spanish
Lagos de Moreno Mexico Spanish
Lalitapur Nepal Nepali
Las Margaritas Mexico Spanish
Las Palmas de Gran Canaria Spain Spanish
Lashio (Lasho) Myanmar Burmese
Lauro de Freitas Brazil Portuguese
Lengshuijiang China Chinese
Leninsk-Kuznetski Russian Federation Russian
Leverkusen Germany German
Lexington-Fayette United States English
Liangcheng China Chinese
Lianyungang China Chinese
Little Rock United States English
Liupanshui China Chinese
Lleida (Lérida) Spain Spanish
Lomas de Zamora Argentina Spanish
Long Beach United States English
Los Angeles Chile Spanish
Los Angeles United States English
Los Teques Venezuela Spanish
Louisville United States English
Lower Hutt New Zealand English
Luchou Taiwan Min
Ludwigshafen am Rhein Germany German
Lungtan Taiwan Min
L´Hospitalet de Llobregat Spain Spanish
Lázaro Cárdenas Mexico Spanish
set join_cache_level=3;
show variables like 'join_cache_level';
Variable_name Value
join_cache_level 3
EXPLAIN
SELECT City.Name, Country.Name FROM City,Country
WHERE City.Country=Country.Code AND
Country.Name LIKE 'L%' AND City.Population > 100000;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE Country ALL NULL NULL NULL NULL 239 Using where
1 SIMPLE City hash_ALL NULL #hash#$hj 3 world.Country.Code 4079 Using where; Using join buffer (flat, BNLH join)
SELECT City.Name, Country.Name FROM City,Country
WHERE City.Country=Country.Code AND
Country.Name LIKE 'L%' AND City.Population > 100000;
Name Name
?iauliai Lithuania
Beirut Lebanon
Bengasi Libyan Arab Jamahiriya
Daugavpils Latvia
Kaunas Lithuania
Klaipeda Lithuania
Maseru Lesotho
Misrata Libyan Arab Jamahiriya
Monrovia Liberia
Panevezys Lithuania
Riga Latvia
Tripoli Lebanon
Tripoli Libyan Arab Jamahiriya
Vientiane Laos
Vilnius Lithuania
EXPLAIN
SELECT City.Name, Country.Name, CountryLanguage.Language
FROM City,Country,CountryLanguage
WHERE City.Country=Country.Code AND
CountryLanguage.Country=Country.Code AND
City.Name LIKE 'L%' AND Country.Population > 3000000 AND
CountryLanguage.Percentage > 50 AND
LENGTH(Language) < LENGTH(City.Name) - 2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE Country ALL NULL NULL NULL NULL 239 Using where
1 SIMPLE CountryLanguage hash_ALL NULL #hash#$hj 3 world.Country.Code 984 Using where; Using join buffer (flat, BNLH join)
1 SIMPLE City hash_ALL NULL #hash#$hj 3 world.Country.Code 4079 Using where; Using join buffer (flat, BNLH join)
SELECT City.Name, Country.Name, CountryLanguage.Language
FROM City,Country,CountryLanguage
WHERE City.Country=Country.Code AND
CountryLanguage.Country=Country.Code AND
City.Name LIKE 'L%' AND Country.Population > 3000000 AND
CountryLanguage.Percentage > 50 AND
LENGTH(Language) < LENGTH(City.Name) - 2;
Name Name Language
La Matanza Argentina Spanish
Lagos de Moreno Mexico Spanish
Lalitapur Nepal Nepali
Las Margaritas Mexico Spanish
Las Palmas de Gran Canaria Spain Spanish
Lashio (Lasho) Myanmar Burmese
Lauro de Freitas Brazil Portuguese
Lengshuijiang China Chinese
Leninsk-Kuznetski Russian Federation Russian
Leverkusen Germany German
Lexington-Fayette United States English
Liangcheng China Chinese
Lianyungang China Chinese
Little Rock United States English
Liupanshui China Chinese
Lleida (Lérida) Spain Spanish
Lomas de Zamora Argentina Spanish
Long Beach United States English
Los Angeles Chile Spanish
Los Angeles United States English
Los Teques Venezuela Spanish
Louisville United States English
Lower Hutt New Zealand English
Luchou Taiwan Min
Ludwigshafen am Rhein Germany German
Lungtan Taiwan Min
L´Hospitalet de Llobregat Spain Spanish
Lázaro Cárdenas Mexico Spanish
set join_cache_level=4;
show variables like 'join_cache_level';
Variable_name Value
join_cache_level 4
EXPLAIN
SELECT City.Name, Country.Name FROM City,Country
WHERE City.Country=Country.Code AND
Country.Name LIKE 'L%' AND City.Population > 100000;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE Country ALL NULL NULL NULL NULL 239 Using where
1 SIMPLE City hash_ALL NULL #hash#$hj 3 world.Country.Code 4079 Using where; Using join buffer (flat, BNLH join)
SELECT City.Name, Country.Name FROM City,Country
WHERE City.Country=Country.Code AND
Country.Name LIKE 'L%' AND City.Population > 100000;
Name Name
?iauliai Lithuania
Beirut Lebanon
Bengasi Libyan Arab Jamahiriya
Daugavpils Latvia
Kaunas Lithuania
Klaipeda Lithuania
Maseru Lesotho
Misrata Libyan Arab Jamahiriya
Monrovia Liberia
Panevezys Lithuania
Riga Latvia
Tripoli Lebanon
Tripoli Libyan Arab Jamahiriya
Vientiane Laos
Vilnius Lithuania
EXPLAIN
SELECT City.Name, Country.Name, CountryLanguage.Language
FROM City,Country,CountryLanguage
WHERE City.Country=Country.Code AND
CountryLanguage.Country=Country.Code AND
City.Name LIKE 'L%' AND Country.Population > 3000000 AND
CountryLanguage.Percentage > 50 AND
LENGTH(Language) < LENGTH(City.Name) - 2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE Country ALL NULL NULL NULL NULL 239 Using where
1 SIMPLE CountryLanguage hash_ALL NULL #hash#$hj 3 world.Country.Code 984 Using where; Using join buffer (flat, BNLH join)
1 SIMPLE City hash_ALL NULL #hash#$hj 3 world.Country.Code 4079 Using where; Using join buffer (incremental, BNLH join)
SELECT City.Name, Country.Name, CountryLanguage.Language
FROM City,Country,CountryLanguage
WHERE City.Country=Country.Code AND
CountryLanguage.Country=Country.Code AND
City.Name LIKE 'L%' AND Country.Population > 3000000 AND
CountryLanguage.Percentage > 50 AND
LENGTH(Language) < LENGTH(City.Name) - 2;
Name Name Language
La Matanza Argentina Spanish
Lagos de Moreno Mexico Spanish
Lalitapur Nepal Nepali
Las Margaritas Mexico Spanish
Las Palmas de Gran Canaria Spain Spanish
Lashio (Lasho) Myanmar Burmese
Lauro de Freitas Brazil Portuguese
Lengshuijiang China Chinese
Leninsk-Kuznetski Russian Federation Russian
Leverkusen Germany German
Lexington-Fayette United States English
Liangcheng China Chinese
Lianyungang China Chinese
Little Rock United States English
Liupanshui China Chinese
Lleida (Lérida) Spain Spanish
Lomas de Zamora Argentina Spanish
Long Beach United States English
Los Angeles Chile Spanish
Los Angeles United States English
Los Teques Venezuela Spanish
Louisville United States English
Lower Hutt New Zealand English
Luchou Taiwan Min
Ludwigshafen am Rhein Germany German
Lungtan Taiwan Min
L´Hospitalet de Llobregat Spain Spanish
Lázaro Cárdenas Mexico Spanish
SELECT Country.Name, Country.Population, City.Name, City.Population
FROM Country LEFT JOIN City
ON City.Country=Country.Code AND City.Population > 5000000
WHERE Country.Name LIKE 'C%' AND Country.Population > 10000000;
Name Population Name Population
China 1277558000 Shanghai 9696300
China 1277558000 Peking 7472000
China 1277558000 Chongqing 6351600
China 1277558000 Tianjin 5286800
Colombia 42321000 Santafé de Bogotá 6260862
Congo, The Democratic Republic of the 51654000 Kinshasa 5064000
Chile 15211000 NULL NULL
Cambodia 11168000 NULL NULL
Cameroon 15085000 NULL NULL
Canada 31147000 NULL NULL
Cuba 11201000 NULL NULL
Côte d?Ivoire 14786000 NULL NULL
Czech Republic 10278100 NULL NULL
SELECT Country.Name, Country.Population, City.Name, City.Population
FROM Country LEFT JOIN City
ON City.Country=Country.Code AND
(City.Population > 5000000 OR City.Name LIKE 'Za%')
WHERE Country.Name LIKE 'C%' AND Country.Population > 10000000;
Name Population Name Population
China 1277558000 Shanghai 9696300
China 1277558000 Peking 7472000
China 1277558000 Chongqing 6351600
China 1277558000 Tianjin 5286800
China 1277558000 Zaozhuang 380846
China 1277558000 Zaoyang 162198
China 1277558000 Zalantun 130031
Colombia 42321000 Santafé de Bogotá 6260862
Congo, The Democratic Republic of the 51654000 Kinshasa 5064000
Chile 15211000 NULL NULL
Cambodia 11168000 NULL NULL
Cameroon 15085000 NULL NULL
Canada 31147000 NULL NULL
Cuba 11201000 NULL NULL
Côte d?Ivoire 14786000 NULL NULL
Czech Republic 10278100 NULL NULL
CREATE INDEX City_Population ON City(Population);
CREATE INDEX City_Name ON City(Name);
ANALYZE TABLE City;
EXPLAIN
SELECT Country.Name, Country.Population, City.Name, City.Population
FROM Country LEFT JOIN City
ON City.Country=Country.Code AND City.Population > 5000000
WHERE Country.Name LIKE 'C%' AND Country.Population > 10000000;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE Country ALL NULL NULL NULL NULL 239 Using where
1 SIMPLE City hash_range City_Population #hash#$hj:City_Population 3:4 world.Country.Code 24 Using where; Rowid-ordered scan; Using join buffer (flat, BNLH join)
SELECT Country.Name, Country.Population, City.Name, City.Population
FROM Country LEFT JOIN City
ON City.Country=Country.Code AND City.Population > 5000000
WHERE Country.Name LIKE 'C%' AND Country.Population > 10000000;
Name Population Name Population
China 1277558000 Shanghai 9696300
China 1277558000 Peking 7472000
China 1277558000 Chongqing 6351600
China 1277558000 Tianjin 5286800
Colombia 42321000 Santafé de Bogotá 6260862
Congo, The Democratic Republic of the 51654000 Kinshasa 5064000
Chile 15211000 NULL NULL
Cambodia 11168000 NULL NULL
Cameroon 15085000 NULL NULL
Canada 31147000 NULL NULL
Cuba 11201000 NULL NULL
Côte d?Ivoire 14786000 NULL NULL
Czech Republic 10278100 NULL NULL
EXPLAIN
SELECT Country.Name, Country.Population, City.Name, City.Population
FROM Country LEFT JOIN City
ON City.Country=Country.Code AND
(City.Population > 5000000 OR City.Name LIKE 'Za%')
WHERE Country.Name LIKE 'C%' AND Country.Population > 10000000;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE Country ALL NULL NULL NULL NULL 239 Using where
1 SIMPLE City hash_index_merge City_Population,City_Name #hash#$hj:City_Population,City_Name 3:4,35 world.Country.Code 96 Using sort_union(City_Population,City_Name); Using where; Using join buffer (flat, BNLH join)
SELECT Country.Name, Country.Population, City.Name, City.Population
FROM Country LEFT JOIN City
ON City.Country=Country.Code AND
(City.Population > 5000000 OR City.Name LIKE 'Za%')
WHERE Country.Name LIKE 'C%' AND Country.Population > 10000000;
Name Population Name Population
China 1277558000 Shanghai 9696300
China 1277558000 Peking 7472000
China 1277558000 Chongqing 6351600
China 1277558000 Tianjin 5286800
China 1277558000 Zaozhuang 380846
China 1277558000 Zaoyang 162198
China 1277558000 Zalantun 130031
Colombia 42321000 Santafé de Bogotá 6260862
Congo, The Democratic Republic of the 51654000 Kinshasa 5064000
Chile 15211000 NULL NULL
Cambodia 11168000 NULL NULL
Cameroon 15085000 NULL NULL
Canada 31147000 NULL NULL
Cuba 11201000 NULL NULL
Côte d?Ivoire 14786000 NULL NULL
Czech Republic 10278100 NULL NULL
DROP INDEX City_Population ON City;
DROP INDEX City_Name ON City;
set join_cache_level=1;
set join_buffer_size=256;
show variables like 'join_buffer_size';
Variable_name Value
join_buffer_size 256
show variables like 'join_cache_level';
Variable_name Value
join_cache_level 1
EXPLAIN
SELECT City.Name, Country.Name FROM City,Country
WHERE City.Country=Country.Code AND
Country.Name LIKE 'L%' AND City.Population > 100000;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE Country ALL NULL NULL NULL NULL 239 Using where
1 SIMPLE City ALL NULL NULL NULL NULL 4079 Using where; Using join buffer (flat, BNL join)
SELECT City.Name, Country.Name FROM City,Country
WHERE City.Country=Country.Code AND
Country.Name LIKE 'L%' AND City.Population > 100000;
Name Name
?iauliai Lithuania
Beirut Lebanon
Bengasi Libyan Arab Jamahiriya
Daugavpils Latvia
Kaunas Lithuania
Klaipeda Lithuania
Maseru Lesotho
Misrata Libyan Arab Jamahiriya
Monrovia Liberia
Panevezys Lithuania
Riga Latvia
Tripoli Lebanon
Tripoli Libyan Arab Jamahiriya
Vientiane Laos
Vilnius Lithuania
EXPLAIN
SELECT City.Name, Country.Name, CountryLanguage.Language
FROM City,Country,CountryLanguage
WHERE City.Country=Country.Code AND
CountryLanguage.Country=Country.Code AND
City.Name LIKE 'L%' AND Country.Population > 3000000 AND
CountryLanguage.Percentage > 50 AND
LENGTH(Language) < LENGTH(City.Name) - 2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE Country ALL NULL NULL NULL NULL 239 Using where
1 SIMPLE CountryLanguage ALL NULL NULL NULL NULL 984 Using where; Using join buffer (flat, BNL join)
1 SIMPLE City ALL NULL NULL NULL NULL 4079 Using where; Using join buffer (flat, BNL join)
SELECT City.Name, Country.Name, CountryLanguage.Language
FROM City,Country,CountryLanguage
WHERE City.Country=Country.Code AND
CountryLanguage.Country=Country.Code AND
City.Name LIKE 'L%' AND Country.Population > 3000000 AND
CountryLanguage.Percentage > 50 AND
LENGTH(Language) < LENGTH(City.Name) - 2;
Name Name Language
La Matanza Argentina Spanish
Lagos de Moreno Mexico Spanish
Lalitapur Nepal Nepali
Las Margaritas Mexico Spanish
Las Palmas de Gran Canaria Spain Spanish
Lashio (Lasho) Myanmar Burmese
Lauro de Freitas Brazil Portuguese
Lengshuijiang China Chinese
Leninsk-Kuznetski Russian Federation Russian
Leverkusen Germany German
Lexington-Fayette United States English
Liangcheng China Chinese
Lianyungang China Chinese
Little Rock United States English
Liupanshui China Chinese
Lleida (Lérida) Spain Spanish
Lomas de Zamora Argentina Spanish
Long Beach United States English
Los Angeles Chile Spanish
Los Angeles United States English
Los Teques Venezuela Spanish
Louisville United States English
Lower Hutt New Zealand English
Luchou Taiwan Min
Ludwigshafen am Rhein Germany German
Lungtan Taiwan Min
L´Hospitalet de Llobregat Spain Spanish
Lázaro Cárdenas Mexico Spanish
set join_cache_level=2;
show variables like 'join_cache_level';
Variable_name Value
join_cache_level 2
EXPLAIN
SELECT City.Name, Country.Name FROM City,Country
WHERE City.Country=Country.Code AND
Country.Name LIKE 'L%' AND City.Population > 100000;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE Country ALL NULL NULL NULL NULL 239 Using where
1 SIMPLE City ALL NULL NULL NULL NULL 4079 Using where; Using join buffer (flat, BNL join)
SELECT City.Name, Country.Name FROM City,Country
WHERE City.Country=Country.Code AND
Country.Name LIKE 'L%' AND City.Population > 100000;
Name Name
?iauliai Lithuania
Beirut Lebanon
Bengasi Libyan Arab Jamahiriya
Daugavpils Latvia
Kaunas Lithuania
Klaipeda Lithuania
Maseru Lesotho
Misrata Libyan Arab Jamahiriya
Monrovia Liberia
Panevezys Lithuania
Riga Latvia
Tripoli Lebanon
Tripoli Libyan Arab Jamahiriya
Vientiane Laos
Vilnius Lithuania
EXPLAIN
SELECT City.Name, Country.Name, CountryLanguage.Language
FROM City,Country,CountryLanguage
WHERE City.Country=Country.Code AND
CountryLanguage.Country=Country.Code AND
City.Name LIKE 'L%' AND Country.Population > 3000000 AND
CountryLanguage.Percentage > 50 AND
LENGTH(Language) < LENGTH(City.Name) - 2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE Country ALL NULL NULL NULL NULL 239 Using where
1 SIMPLE CountryLanguage ALL NULL NULL NULL NULL 984 Using where; Using join buffer (flat, BNL join)
1 SIMPLE City ALL NULL NULL NULL NULL 4079 Using where; Using join buffer (incremental, BNL join)
SELECT City.Name, Country.Name, CountryLanguage.Language
FROM City,Country,CountryLanguage
WHERE City.Country=Country.Code AND
CountryLanguage.Country=Country.Code AND
City.Name LIKE 'L%' AND Country.Population > 3000000 AND
CountryLanguage.Percentage > 50 AND
LENGTH(Language) < LENGTH(City.Name) - 2;
Name Name Language
La Matanza Argentina Spanish
Lagos de Moreno Mexico Spanish
Lalitapur Nepal Nepali
Las Margaritas Mexico Spanish
Las Palmas de Gran Canaria Spain Spanish
Lashio (Lasho) Myanmar Burmese
Lauro de Freitas Brazil Portuguese
Lengshuijiang China Chinese
Leninsk-Kuznetski Russian Federation Russian
Leverkusen Germany German
Lexington-Fayette United States English
Liangcheng China Chinese
Lianyungang China Chinese
Little Rock United States English
Liupanshui China Chinese
Lleida (Lérida) Spain Spanish
Lomas de Zamora Argentina Spanish
Long Beach United States English
Los Angeles Chile Spanish
Los Angeles United States English
Los Teques Venezuela Spanish
Louisville United States English
Lower Hutt New Zealand English
Luchou Taiwan Min
Ludwigshafen am Rhein Germany German
Lungtan Taiwan Min
L´Hospitalet de Llobregat Spain Spanish
Lázaro Cárdenas Mexico Spanish
set join_cache_level=3;
show variables like 'join_cache_level';
Variable_name Value
join_cache_level 3
EXPLAIN
SELECT City.Name, Country.Name FROM City,Country
WHERE City.Country=Country.Code AND
Country.Name LIKE 'L%' AND City.Population > 100000;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE Country ALL NULL NULL NULL NULL 239 Using where
1 SIMPLE City hash_ALL NULL #hash#$hj 3 world.Country.Code 4079 Using where; Using join buffer (flat, BNLH join)
SELECT City.Name, Country.Name FROM City,Country
WHERE City.Country=Country.Code AND
Country.Name LIKE 'L%' AND City.Population > 100000;
Name Name
?iauliai Lithuania
Beirut Lebanon
Bengasi Libyan Arab Jamahiriya
Daugavpils Latvia
Kaunas Lithuania
Klaipeda Lithuania
Maseru Lesotho
Misrata Libyan Arab Jamahiriya
Monrovia Liberia
Panevezys Lithuania
Riga Latvia
Tripoli Lebanon
Tripoli Libyan Arab Jamahiriya
Vientiane Laos
Vilnius Lithuania
EXPLAIN
SELECT City.Name, Country.Name, CountryLanguage.Language
FROM City,Country,CountryLanguage
WHERE City.Country=Country.Code AND
CountryLanguage.Country=Country.Code AND
City.Name LIKE 'L%' AND Country.Population > 3000000 AND
CountryLanguage.Percentage > 50 AND
LENGTH(Language) < LENGTH(City.Name) - 2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE Country ALL NULL NULL NULL NULL 239 Using where
1 SIMPLE CountryLanguage hash_ALL NULL #hash#$hj 3 world.Country.Code 984 Using where; Using join buffer (flat, BNLH join)
1 SIMPLE City hash_ALL NULL #hash#$hj 3 world.Country.Code 4079 Using where; Using join buffer (flat, BNLH join)
SELECT City.Name, Country.Name, CountryLanguage.Language
FROM City,Country,CountryLanguage
WHERE City.Country=Country.Code AND
CountryLanguage.Country=Country.Code AND
City.Name LIKE 'L%' AND Country.Population > 3000000 AND
CountryLanguage.Percentage > 50 AND
LENGTH(Language) < LENGTH(City.Name) - 2;
Name Name Language
La Matanza Argentina Spanish
Lagos de Moreno Mexico Spanish
Lalitapur Nepal Nepali
Las Margaritas Mexico Spanish
Las Palmas de Gran Canaria Spain Spanish
Lashio (Lasho) Myanmar Burmese
Lauro de Freitas Brazil Portuguese
Lengshuijiang China Chinese
Leninsk-Kuznetski Russian Federation Russian
Leverkusen Germany German
Lexington-Fayette United States English
Liangcheng China Chinese
Lianyungang China Chinese
Little Rock United States English
Liupanshui China Chinese
Lleida (Lérida) Spain Spanish
Lomas de Zamora Argentina Spanish
Long Beach United States English
Los Angeles Chile Spanish
Los Angeles United States English
Los Teques Venezuela Spanish
Louisville United States English
Lower Hutt New Zealand English
Luchou Taiwan Min
Ludwigshafen am Rhein Germany German
Lungtan Taiwan Min
L´Hospitalet de Llobregat Spain Spanish
Lázaro Cárdenas Mexico Spanish
set join_cache_level=4;
show variables like 'join_cache_level';
Variable_name Value
join_cache_level 4
EXPLAIN
SELECT City.Name, Country.Name FROM City,Country
WHERE City.Country=Country.Code AND
Country.Name LIKE 'L%' AND City.Population > 100000;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE Country ALL NULL NULL NULL NULL 239 Using where
1 SIMPLE City hash_ALL NULL #hash#$hj 3 world.Country.Code 4079 Using where; Using join buffer (flat, BNLH join)
SELECT City.Name, Country.Name FROM City,Country
WHERE City.Country=Country.Code AND
Country.Name LIKE 'L%' AND City.Population > 100000;
Name Name
?iauliai Lithuania
Beirut Lebanon
Bengasi Libyan Arab Jamahiriya
Daugavpils Latvia
Kaunas Lithuania
Klaipeda Lithuania
Maseru Lesotho
Misrata Libyan Arab Jamahiriya
Monrovia Liberia
Panevezys Lithuania
Riga Latvia
Tripoli Lebanon
Tripoli Libyan Arab Jamahiriya
Vientiane Laos
Vilnius Lithuania
EXPLAIN
SELECT City.Name, Country.Name, CountryLanguage.Language
FROM City,Country,CountryLanguage
WHERE City.Country=Country.Code AND
CountryLanguage.Country=Country.Code AND
City.Name LIKE 'L%' AND Country.Population > 3000000 AND
CountryLanguage.Percentage > 50 AND
LENGTH(Language) < LENGTH(City.Name) - 2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE Country ALL NULL NULL NULL NULL 239 Using where
1 SIMPLE CountryLanguage hash_ALL NULL #hash#$hj 3 world.Country.Code 984 Using where; Using join buffer (flat, BNLH join)
1 SIMPLE City hash_ALL NULL #hash#$hj 3 world.Country.Code 4079 Using where; Using join buffer (incremental, BNLH join)
SELECT City.Name, Country.Name, CountryLanguage.Language
FROM City,Country,CountryLanguage
WHERE City.Country=Country.Code AND
CountryLanguage.Country=Country.Code AND
City.Name LIKE 'L%' AND Country.Population > 3000000 AND
CountryLanguage.Percentage > 50 AND
LENGTH(Language) < LENGTH(City.Name) - 2;
Name Name Language
La Matanza Argentina Spanish
Lagos de Moreno Mexico Spanish
Lalitapur Nepal Nepali
Las Margaritas Mexico Spanish
Las Palmas de Gran Canaria Spain Spanish
Lashio (Lasho) Myanmar Burmese
Lauro de Freitas Brazil Portuguese
Lengshuijiang China Chinese
Leninsk-Kuznetski Russian Federation Russian
Leverkusen Germany German
Lexington-Fayette United States English
Liangcheng China Chinese
Lianyungang China Chinese
Little Rock United States English
Liupanshui China Chinese
Lleida (Lérida) Spain Spanish
Lomas de Zamora Argentina Spanish
Long Beach United States English
Los Angeles Chile Spanish
Los Angeles United States English
Los Teques Venezuela Spanish
Louisville United States English
Lower Hutt New Zealand English
Luchou Taiwan Min
Ludwigshafen am Rhein Germany German
Lungtan Taiwan Min
L´Hospitalet de Llobregat Spain Spanish
Lázaro Cárdenas Mexico Spanish
set join_cache_level=@save_join_cache_level;
set join_buffer_size=@save_join_buffer_size;
DROP DATABASE world;
CREATE DATABASE world;
use world;
CREATE TABLE Country (
Code char(3) NOT NULL default '',
Name char(52) NOT NULL default '',
SurfaceArea float(10,2) NOT NULL default '0.00',
Population int(11) NOT NULL default '0',
Capital int(11) default NULL,
PRIMARY KEY (Code),
UNIQUE INDEX (Name)
);
CREATE TABLE City (
ID int(11) NOT NULL auto_increment,
Name char(35) NOT NULL default '',
Country char(3) NOT NULL default '',
Population int(11) NOT NULL default '0',
PRIMARY KEY (ID),
INDEX (Population),
INDEX (Country)
);
CREATE TABLE CountryLanguage (
Country char(3) NOT NULL default '',
Language char(30) NOT NULL default '',
Percentage float(3,1) NOT NULL default '0.0',
PRIMARY KEY (Country, Language),
INDEX (Percentage)
);
show variables like 'join_buffer_size';
Variable_name Value
join_buffer_size 262144
set join_cache_level=3;
show variables like 'join_cache_level';
Variable_name Value
join_cache_level 3
EXPLAIN
SELECT City.Name, Country.Name FROM City,Country
WHERE City.Country=Country.Code AND
Country.Name LIKE 'L%' AND City.Population > 100000;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE Country range PRIMARY,Name Name 52 NULL 10 Using index condition; Rowid-ordered scan
1 SIMPLE City hash_ALL Population,Country #hash#Country 3 world.Country.Code 4079 Using where; Using join buffer (flat, BNLH join)
SELECT City.Name, Country.Name FROM City,Country
WHERE City.Country=Country.Code AND
Country.Name LIKE 'L%' AND City.Population > 100000;
Name Name
?iauliai Lithuania
Beirut Lebanon
Bengasi Libyan Arab Jamahiriya
Daugavpils Latvia
Kaunas Lithuania
Klaipeda Lithuania
Maseru Lesotho
Misrata Libyan Arab Jamahiriya
Monrovia Liberia
Panevezys Lithuania
Riga Latvia
Tripoli Lebanon
Tripoli Libyan Arab Jamahiriya
Vientiane Laos
Vilnius Lithuania
EXPLAIN
SELECT City.Name, Country.Name, CountryLanguage.Language
FROM City,Country,CountryLanguage
WHERE City.Country=Country.Code AND
CountryLanguage.Country=Country.Code AND
City.Name LIKE 'L%' AND Country.Population > 3000000 AND
CountryLanguage.Percentage > 50 AND
LENGTH(Language) < LENGTH(City.Name) - 2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE City ALL Country NULL NULL NULL 4079 Using where
1 SIMPLE Country hash_ALL PRIMARY #hash#PRIMARY 3 world.City.Country 239 Using where; Using join buffer (flat, BNLH join)
1 SIMPLE CountryLanguage hash_ALL|filter PRIMARY,Percentage #hash#PRIMARY|Percentage 3|4 world.City.Country 984 (19%) Using where; Using join buffer (flat, BNLH join); Using rowid filter
SELECT City.Name, Country.Name, CountryLanguage.Language
FROM City,Country,CountryLanguage
WHERE City.Country=Country.Code AND
CountryLanguage.Country=Country.Code AND
City.Name LIKE 'L%' AND Country.Population > 3000000 AND
CountryLanguage.Percentage > 50 AND
LENGTH(Language) < LENGTH(City.Name) - 2;
Name Name Language
La Matanza Argentina Spanish
Lagos de Moreno Mexico Spanish
Lalitapur Nepal Nepali
Las Margaritas Mexico Spanish
Las Palmas de Gran Canaria Spain Spanish
Lashio (Lasho) Myanmar Burmese
Lauro de Freitas Brazil Portuguese
Lengshuijiang China Chinese
Leninsk-Kuznetski Russian Federation Russian
Leverkusen Germany German
Lexington-Fayette United States English
Liangcheng China Chinese
Lianyungang China Chinese
Little Rock United States English
Liupanshui China Chinese
Lleida (Lérida) Spain Spanish
Lomas de Zamora Argentina Spanish
Long Beach United States English
Los Angeles Chile Spanish
Los Angeles United States English
Los Teques Venezuela Spanish
Louisville United States English
Lower Hutt New Zealand English
Luchou Taiwan Min
Ludwigshafen am Rhein Germany German
Lungtan Taiwan Min
L´Hospitalet de Llobregat Spain Spanish
Lázaro Cárdenas Mexico Spanish
EXPLAIN
SELECT Name FROM City
WHERE City.Country IN (SELECT Code FROM Country WHERE Country.Name LIKE 'L%') AND
City.Population > 100000;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY Country range PRIMARY,Name Name 52 NULL 10 Using index condition; Rowid-ordered scan
1 PRIMARY City hash_ALL Population,Country #hash#Country 3 world.Country.Code 4079 Using where; Using join buffer (flat, BNLH join)
SELECT Name FROM City
WHERE City.Country IN (SELECT Code FROM Country WHERE Country.Name LIKE 'L%') AND
City.Population > 100000;
Name
Vientiane
Riga
Daugavpils
Maseru
Beirut
Tripoli
Monrovia
Tripoli
Bengasi
Misrata
Vilnius
Kaunas
Klaipeda
?iauliai
Panevezys
EXPLAIN
SELECT Country.Name, IF(ISNULL(CountryLanguage.Country), NULL, CountryLanguage.Percentage)
FROM Country LEFT JOIN CountryLanguage ON
(CountryLanguage.Country=Country.Code AND Language='English')
WHERE
Country.Population > 10000000;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE Country ALL NULL NULL NULL NULL 239 Using where
1 SIMPLE CountryLanguage hash_ALL PRIMARY #hash#PRIMARY 33 world.Country.Code,const 984 Using where; Using join buffer (flat, BNLH join)
SELECT Country.Name, IF(ISNULL(CountryLanguage.Country), NULL, CountryLanguage.Percentage)
FROM Country LEFT JOIN CountryLanguage ON
(CountryLanguage.Country=Country.Code AND Language='English')
WHERE
Country.Population > 10000000;
Name IF(ISNULL(CountryLanguage.Country), NULL, CountryLanguage.Percentage)
Australia 81.2
United Kingdom 97.3
Canada 60.4
United States 86.2
Zimbabwe 2.2
Japan 0.1
South Africa 8.5
Malaysia 1.6
Afghanistan NULL
Netherlands NULL
Algeria NULL
Angola NULL
Argentina NULL
Bangladesh NULL
Belgium NULL
Brazil NULL
Burkina Faso NULL
Chile NULL
Ecuador NULL
Egypt NULL
Spain NULL
Ethiopia NULL
Philippines NULL
Ghana NULL
Guatemala NULL
Indonesia NULL
India NULL
Iraq NULL
Iran NULL
Italy NULL
Yemen NULL
Yugoslavia NULL
Cambodia NULL
Cameroon NULL
Kazakstan NULL
Kenya NULL
China NULL
Colombia NULL
Congo, The Democratic Republic of the NULL
North Korea NULL
South Korea NULL
Greece NULL
Cuba NULL
Madagascar NULL
Malawi NULL
Mali NULL
Morocco NULL
Mexico NULL
Mozambique NULL
Myanmar NULL
Nepal NULL
Niger NULL
Nigeria NULL
Côte d?Ivoire NULL
Pakistan NULL
Peru NULL
Poland NULL
France NULL
Romania NULL
Germany NULL
Saudi Arabia NULL
Somalia NULL
Sri Lanka NULL
Sudan NULL
Syria NULL
Taiwan NULL
Tanzania NULL