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SQL part1

 1)To get all items from the table:

SELECT * FROM tablename;


2)To get specific fields from the table:

SELECT CustomerName, City FROM Customers;


3)Select distinct values for a column from a table:

SELECT DISTINCT Country FROM Customers;


4)Get the count of distinct values for  a column from a table:

SELECT COUNT(DISTINCT Country) FROM Customers;

5)Where conditions to get data from the table:

SELECT * FROM Customers
WHERE Country='Mexico';

6)Where with and and or ,not :

SELECT * FROM Customers
WHERE Country='Germany' AND City='Berlin';

SELECT * FROM Customers
WHERE City='Berlin' OR City='München';

SELECT * FROM Customers
WHERE NOT Country='Germany';

7)Sorting by default ascending

SELECT * FROM Customers
ORDER BY Country;

SELECT * FROM Customers
ORDER BY Country DESC;

SELECT * FROM Customers
ORDER BY Country ASC, CustomerName DESC;

8)Insert
INSERT INTO Customers (CustomerName, ContactName, Address, City, PostalCode, Country)
VALUES ('Cardinal','Tom B. Erichsen','Skagen 21','Stavanger','4006','Norway');

INSERT INTO Customers (CustomerName, City, Country)
VALUES ('Cardinal', 'Stavanger', 'Norway');

9)NUll Values:

SELECT CustomerName, ContactName, Address
FROM Customers
WHERE Address IS NULL;

SELECT CustomerName, ContactName, Address
FROM Customers
WHERE Address IS NOT NULL;


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