first commit

Advanced Select/Binary Tree Nodes.sql

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+SELECT N,
+(
+ CASE
+ WHEN P IS NULL THEN "Root"
+ WHEN N NOT IN (SELECT P FROM BST WHERE P IS NOT NULL) THEN "Leaf"
+ ELSE "Inner"
+ END
+)
+FROM BST
+ORDER BY N

Advanced Select/The PADS.sql

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+/*
+1. Query an alphabetically ordered list of all names in OCCUPATIONS, immediately followed by the first letter of each profession as a parenthetical (i.e.: enclosed in parentheses). For example: AnActorName(A), ADoctorName(D), AProfessorName(P), and ASingerName(S).
+Example: 
+Ashely(P)
+Christeen(P)
+Jane(A)
+Jenny(D)
+*/
+SELECT CONCAT(Name,'(',CASE
+ WHEN Occupation = 'Actor' THEN 'A'
+ WHEN Occupation = 'Doctor' THEN 'D'
+ WHEN Occupation = 'Singer' THEN 'S'
+ WHEN Occupation = 'Professor' THEN 'P'
+END,')') FROM OCCUPATIONS 
+ORDER BY Name;
+
+/*
+2.Query the number of ocurrences of each occupation in OCCUPATIONS. Sort the occurrences in ascending order, and output them in the following format:
+
+There are a total of [occupation_count] [occupation]s.
+
+where [occupation_count] is the number of occurrences of an occupation in OCCUPATIONS and [occupation] is the lowercase occupation name. If more than one Occupation has the same [occupation_count], they should be ordered alphabetically.
+*/
+
+SELECT CONCAT('There are a total of ',COUNT(occupation),' ',LOWER(occupation),'s.')
+FROM OCCUPATIONS
+GROUP BY occupation
+ORDER BY COUNT(occupation) ASC, occupation ASC

Advanced Select/Type of Triangle.sql

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+SELECT CASE 
+ WHEN A + B > C AND B + C > A AND A + C > B THEN
+ CASE 
+ WHEN A = B AND B = C THEN 'Equilateral'
+ WHEN A = B OR B = C OR A = C THEN 'Isosceles'
+ ELSE 'Scalene'
+ END
+ ELSE 'Not A Triangle'
+ END
+FROM TRIANGLES;

Aggregation/Average Population.sql

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+SELECT ROUND(AVG(POPULATION)) FROM CITY

Aggregation/Japan Population.sql

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+SELECT SUM(POPULATION) FROM CITY
+WHERE COUNTRYCODE = 'JPN'

Aggregation/Population Density Difference.sql

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+SELECT (SELECT MAX(POPULATION) FROM CITY) - (SELECT MIN(POPULATION) FROM CITY)

Aggregation/Revising Aggregations - Averages.sql

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+SELECT AVG(POPULATION) FROM CITY
+WHERE DISTRICT = 'California'

Aggregation/Revising Aggregations - The Count Function.sql

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+SELECT COUNT(ID) FROM CITY
+WHERE POPULATION > 100000

Aggregation/Revising Aggregations - The Sum Function.sql

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+SELECT SUM(POPULATION) FROM CITY
+WHERE DISTRICT = 'California'

Aggregation/The Blunder.sql

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+SELECT (SELECT ROUND(AVG(Salary)) FROM EMPLOYEES) - (SELECT ROUND(AVG(REPLACE(Salary, '0', ''))) FROM EMPLOYEES)

Aggregation/Top Earners.sql

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+SELECT MAX(months*salary), COUNT(salary) FROM EMPLOYEE
+WHERE months * salary = (SELECT MAX(months*salary) FROM EMPLOYEE)

Aggregation/Weather Observation Station 13.sql

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+SELECT TRUNCATE(SUM(LAT_N),4) FROM STATION
+WHERE LAT_N > 38.7880 AND LAT_N < 137.2345

Aggregation/Weather Observation Station 14.sql

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+SELECT TRUNCATE(MAX(LAT_N),4) FROM STATION
+WHERE LAT_N < 137.2345

Aggregation/Weather Observation Station 15.sql

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+SELECT ROUND(LONG_W,4) FROM STATION
+WHERE LAT_N = (SELECT MAX(LAT_N) FROM STATION
+ WHERE LAT_N < 137.2345)

Aggregation/Weather Observation Station 16.sql

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+SELECT ROUND(MIN(LAT_N),4) FROM STATION
+WHERE LAT_N > 38.7780

Aggregation/Weather Observation Station 17.sql

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+SELECT ROUND(LONG_W,4) FROM STATION
+WHERE LAT_N > 38.7780
+ORDER BY LAT_N 
+LIMIT 1

Aggregation/Weather Observation Station 18.sql

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+/* 
+p1(x1, y1) and p2(x2, y2)
+|x1 - x2| + |y1 - y2|
+*/
+SELECT ROUND(ABS(MIN(LAT_N) - MAX(LAT_N)) + ABS(MIN(LONG_W) - MAX(LONG_W)),4) FROM STATION

Aggregation/Weather Observation Station 19.sql

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+/*
+p1(min lat, min long) p2(max lat, max long)
+*/
+SELECT ROUND(
+ SQRT(
+ POW(MAX(LAT_N) - MIN(LAT_N),2)+
+ POW(MAX(LONG_W) - MIN(LONG_W),2)
+ )
+ ,4) FROM STATION

Aggregation/Weather Observation Station 2.sql

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+/*
+ROUND(sayi, 2)
+*/
+SELECT ROUND(SUM(LAT_N),2), ROUND(SUM(LONG_W),2)
+FROM STATION

Aggregation/Weather Observation Station 20.sql

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+-- indexes
+SET @lower = CEILING((SELECT COUNT(LAT_N) FROM STATION)/2);
+SET @upper = FLOOR(((SELECT COUNT(LAT_N) FROM STATION)/2)+1);
+
+SET @one = 1;
+SET @lower = @lower - 1;
+
+PREPARE stmt FROM 'SELECT @i := ROUND(LAT_N,4) FROM STATION ORDER BY LAT_N DESC LIMIT ?,?';
+EXECUTE stmt USING @lower, @one;
+
+-- NOT COMPLETED! DATASET COUNT IS ODD SO TEST PASSES. BUT I NEED TO TAKE AVERAGE OF TWO NUMBER FOR EVEN DATASET COUNT

Alternative Queries/Draw The Triangle 1.sql

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+/*
+Enter your query here.
+Please append a semicolon ";" at the end of the query and enter your query in a single line to avoid error.
+*/
+DECLARE @i INTEGER;
+SET @i = 20;
+
+WHILE @i > 0
+BEGIN
+ SELECT REPLICATE('* ', @i);
+ SET @i = @i - 1;
+END;

Alternative Queries/Draw The Triangle 2.sql

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+/*
+Enter your query here.
+Please append a semicolon ";" at the end of the query and enter your query in a single line to avoid error.
+*/
+DECLARE @i INTEGER;
+SET @i = 1;
+
+WHILE @i <= 20
+BEGIN
+ SELECT REPLICATE('* ', @i);
+ SET @i = @i + 1;
+END;

Basic Join/African Cities.sql

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+/*
+query the names of all cities where the CONTINENT is 'Africa'.
+*/
+SELECT NAME FROM CITY
+WHERE COUNTRYCODE IN (SELECT CODE FROM COUNTRY
+ WHERE CONTINENT = 'Africa')

Basic Join/Asian Population.sql

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+/*
+Given the CITY and COUNTRY tables, query the sum of the populations of all cities where the CONTINENT is 'Asia'.
+*/
+SELECT SUM(POPULATION) FROM CITY
+WHERE COUNTRYCODE IN (SELECT CODE FROM COUNTRY
+ WHERE CONTINENT = 'Asia')

Basic Join/Average Population of Each Continent.sql

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+/*
+query the names of all the continents (COUNTRY.Continent) and their respective average city populations (CITY.Population) rounded down to the nearest integer.
+*/
+SELECT CONTINENT, FLOOR(AVG(CITY.POPULATION))
+FROM COUNTRY
+INNER JOIN CITY ON CITY.COUNTRYCODE = COUNTRY.CODE
+GROUP BY CONTINENT

Basic Select/Employee Names.sql

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+SELECT Name FROM Employee
+ORDER BY Name

Basic Select/Employee Salaries.sql

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+SELECT name FROM Employee
+WHERE salary > 2000 AND months < 10
+ORDER BY employee_id ASC

Basic Select/Higher Than 75 Marks.sql

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+SELECT Name FROM STUDENTS
+WHERE Marks > 75
+ORDER BY RIGHT(Name,3), ID ASC

Basic Select/Japanese Cities' Attributes.sql

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+SELECT * FROM CITY
+WHERE COUNTRYCODE = 'JPN'

Basic Select/Japanese Cities' Names.sql

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+SELECT NAME FROM CITY
+WHERE COUNTRYCODE = 'JPN'

Basic Select/Revising the Select Query I.sql

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+SELECT * FROM CITY 
+WHERE COUNTRYCODE = 'USA' AND POPULATION > 100000

Basic Select/Revising the Select Query II.sql

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+SELECT NAME FROM CITY
+WHERE COUNTRYCODE = 'USA' AND POPULATION > 120000

Basic Select/Select All.sql

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+SELECT * FROM CITY

Basic Select/Select By ID.sql

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+SELECT * FROM CITY
+WHERE ID=1661

Basic Select/Weather Observation Station 1.sql

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+SELECT CITY, STATE FROM STATION

Basic Select/Weather Observation Station 10.sql

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+SELECT DISTINCT CITY FROM STATION
+WHERE CITY REGEXP '[^aeiou]$'

Basic Select/Weather Observation Station 11.sql

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+SELECT DISTINCT CITY FROM STATION
+WHERE CITY REGEXP '^[^aeiou]' OR CITY REGEXP '[^aeiou]$'

Basic Select/Weather Observation Station 12.sql

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+SELECT DISTINCT CITY FROM STATION
+WHERE CITY REGEXP '^[^aeiou].*[^aeiou]$'

Basic Select/Weather Observation Station 3.sql

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+SELECT DISTINCT CITY FROM STATION
+WHERE ID%2=0
+ORDER BY CITY 

Basic Select/Weather Observation Station 4.sql

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+SELECT (SELECT COUNT(CITY) FROM STATION) - (SELECT COUNT(DISTINCT CITY) FROM STATION)

Basic Select/Weather Observation Station 5.sql

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+SELECT CITY, LENGTH(CITY) FROM STATION ORDER BY LENGTH(CITY) ASC, CITY LIMIT 1;
+SELECT CITY, LENGTH(CITY) FROM STATION ORDER BY LENGTH(CITY) DESC, CITY LIMIT 1;

Basic Select/Weather Observation Station 6.sql

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+SELECT DISTINCT CITY FROM STATION WHERE CITY REGEXP '^[aeiou]'

Basic Select/Weather Observation Station 7.sql

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+SELECT DISTINCT CITY FROM STATION WHERE CITY REGEXP '[aeiou]$'

Basic Select/Weather Observation Station 8.sql

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+SELECT DISTINCT CITY FROM STATION WHERE CITY REGEXP '^[aeiou].*[aeiou]$'

Basic Select/Weather Observation Station 9.sql

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+SELECT DISTINCT CITY FROM STATION
+WHERE CITY REGEXP '^[^aeiou]'