Create README.md

Case_study_realestate_SQL_Antoine.sql

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+CREATE DATABASE house_price_regression;
+
+USE house_price_regression;
+
+CREATE TABLE house_price_data (
+    id INT,
+    date DATETIME,
+    bedrooms INT,
+    bathrooms FLOAT,
+    sqft_living INT,
+    sqft_lot INT,
+    floors FLOAT,
+    waterfront INT,
+    view INT,
+    `condition` INT,
+    grade INT,
+    sqft_above INT,
+    sqft_basement INT,
+    yr_built INT,
+    yr_renovated INT,
+    zipcode INT,
+    lat FLOAT,
+    `long` FLOAT,
+    sqft_living15 INT,
+    sqft_lot15 INT,
+    price BIGINT,
+    PRIMARY KEY(id)
+);
+
+SHOW VARIABLES LIKE 'local_infile'; -- This query would show you the status of the variable ‘local_infile’. If it is off, use the next command, otherwise you should be good to go
+SHOW VARIABLES LIKE 'secure_file_priv';
+
+ALTER TABLE house_price_data MODIFY id BIGINT;
+ALTER TABLE house_price_data MODIFY date VARCHAR(10);
+
+#Loading of the database from csv to sql
+LOAD DATA INFILE 'C:/ProgramData/MySQL/MySQL Server 8.0/Uploads/regression_data.csv'
+IGNORE INTO TABLE house_price_data
+FIELDS TERMINATED BY ','
+ENCLOSED BY '"'
+LINES TERMINATED BY '\n'
+IGNORE 1 ROWS;
+
+#Check all the data of the database
+select *
+from house_price_data;
+
+#Remove column date
+ALTER TABLE house_price_data
+DROP COLUMN date;
+
+#Count number of values
+SELECT count(*)
+FROM house_price_data;
+
+#Unique values in the column bedrooms
+SELECT
+DISTINCT(bedrooms)
+FROM house_price_data
+ORDER BY bedrooms;
+
+#unique values in the column bathrooms
+SELECT
+DISTINCT(bathrooms)
+FROM house_price_data
+ORDER BY bathrooms;
+
+#Unique values in the column floors
+SELECT
+DISTINCT(floors)
+FROM house_price_data
+ORDER BY floors;
+
+#Unique values in the column condition
+SELECT
+DISTINCT(`condition`)
+FROM house_price_data
+ORDER BY `condition`;
+
+#Unique values in the column grade
+SELECT
+DISTINCT(grade)
+FROM house_price_data
+ORDER BY grade;
+
+
+#IDs of the top 10 most expensive houses in your data.
+SELECT
+id
+FROM house_price_data
+ORDER BY price desc
+LIMIT 10;
+
+#What is the average price of all the properties in your data?
+SELECT 
+avg(price) AS avg_price
+FROM house_price_data;
+
+#Average price of the houses grouped by bedrooms
+SELECT
+bedrooms,
+round(avg(price)) as avg_price
+FROM house_price_data
+GROUP BY bedrooms
+ORDER BY bedrooms;
+
+#What is the average sqft_living of the houses grouped by bedrooms? 
+
+SELECT
+bedrooms,
+round(avg(sqft_living)) as avg_living_space
+FROM house_price_data
+GROUP BY bedrooms
+ORDER BY bedrooms;
+
+#Average price of the houses with a waterfront and without a waterfront
+SELECT 
+    (SELECT round(avg(price)) FROM house_price_data WHERE waterfront = 1) AS 'Price_waterfront',
+    (SELECT round(avg(price)) FROM house_price_data WHERE waterfront = 0) AS 'Price_Wtht_waterfront',
+    ((SELECT round(avg(price)) FROM house_price_data WHERE waterfront = 1) - 
+     (SELECT round(avg(price)) FROM house_price_data WHERE waterfront = 0)) AS 'difference';
+
+
+#Correlation between the columns condition and grade
+
+SELECT
+grade,
+round(avg(`condition`), 2) AS 'Avg_condition'
+FROM house_price_data
+GROUP BY grade
+ORDER BY grade;
+#As we can see there is no correlation between the two variables. We can just say that the lowest grade (3) has the highest average condition
+
+#List of properties that have 3 or 4 bedrooms, more than 3 Bathrooms, One Floor, No waterfront, 3 min for conditions, at least 5 for Grade and less than 300000 euros
+
+SELECT *
+FROM house_price_data 
+WHERE bedrooms IN (3, 4) 
+AND bathrooms > 3 
+AND floors = 1 
+AND waterfront = 0 
+AND `condition` >= 3 
+AND grade >= 5 
+AND price < 300000;
+
+#List of properties whose prices are twice more than the average of all the properties in the database. 
+SELECT *
+FROM house_price_data
+WHERE price >= 2*(SELECT avg(price) FROM house_price_data);
+
+
+#Creation of a view of the query
+CREATE VIEW twice_average_price_view AS
+SELECT *
+FROM house_price_data
+WHERE price >= 2*(SELECT avg(price) FROM house_price_data);
+
+
+#Most customers are interested in properties with three or four bedrooms. What is the difference in average prices of the properties with three and four bedrooms?
+
+SELECT 
+    (SELECT avg(price) FROM house_price_data WHERE bedrooms IN (3, 4)) AS "avg price 3/4 bedroom",
+    (SELECT avg(price) FROM house_price_data) AS "avg price overall",
+    ((SELECT avg(price) FROM house_price_data WHERE bedrooms IN (3, 4)) - 
+     (SELECT avg(price) FROM house_price_data)) AS "difference";
+
+
+#List of the distinct zip codes
+
+SELECT
+distinct(zipcode)
+FROM house_price_data;
+
+#List of all the properties that were renovated.
+SELECT *
+FROM house_price_data
+WHERE yr_renovated > 0;
+
+
+#Provide the details of the property that is the 11th most expensive property in your database.
+
+SELECT *
+FROM house_price_data
+ORDER BY price desc
+LIMIT 11;
+