MySQL练习1

https://sqlzoo.net/wiki/SELECT_names

# 1、Find the country that start with Y
    select name from world where 'Y%';
# 2、Find the countries that end with y
    select name from world where '%y';
# 3、Find the countries that contain the letter x
    select name from world where '%x%';
# 4、Find the countries that end with land
    select name from world where name like '%land';
# 5、Find the countries that start with C and end with ia
    select name from world where name like 'C%ia'
# 6、Find the country that has oo in the name
    select name from world where name like '%oo%'
# 7、Find the countries that have three or more a in the name
    select name from world where name LIKE '%a%a%a%'
# 8、Find the countries that have "t" as the second character.
    select name from world where name like '_t%'
# 9、Find the countries that have two "o" characters separated by two others.
    select name from world where name like '%o__o%'
# 10、Find the countries that have exactly four characters
    select name from world where name like '____'

Harder Questions

# 11、Find the country where the name is the capital city
    select name from world where name=capital
# 12、ind the country where the capital is the country plus "City"
    select name from world where capital = concat(name, ' City')
# 13、Find the capital and the name where the capital includes the name of the country.
(A) select capital, name from world
    where instr(capital, name)
(B) select capital,name from world
    where capital like concat('%',name,'%');
# 14、Find the capital and the name where the capital is an extension of name of the country
(A) select capital,name from world
    where instr(capital,name) and name <> capital
(B) select capital,name from world
    where capital like concat('%',name,'%') and name <> capital;
# 15、Show the name and the extension where the capital is an extension of name of the country
    select name,replace(capital,name,'') ext from world
    where capital like concat(name,'_%');