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SELECT Customers.customer_id, Customers.first_name, Orders.amount
FROM Customers
LEFT JOIN Orders
ON Customers.customer_id = Orders.customer;
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SELECT * FROM
(SELECT [UserID] FROM [User]) a
LEFT JOIN (SELECT [TailUser], [Weight] FROM [Edge] WHERE [HeadUser] = 5043) b
ON a.UserId = b.TailUser
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SELECT Customers.customer_id, Customers.first_name, Orders.amount
FROM Customers
RIGHT JOIN Orders
ON Customers.customer_id = Orders.customer;
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SELECT columns
FROM table1
LEFT JOIN table2
ON table1.column_name = table2.column_name;
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SELECT *
FROM table_1
RIGHT JOIN table_2
ON table_1.common_field = table_2.common_field;
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SELECT * FROM
(SELECT [column] FROM [table]) a
LEFT JOIN (SELECT [column1], [columnn2] FROM [table]) b
ON a.column = b.column1
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SELECT Customers.customer_id, Customers.first_name, Orders.amount
FROM Customers
RIGHT JOIN Orders
ON Customers.customer_id = Orders.customer;
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#LEFT JOIN: Return all rows from the left table, even if there are no matches in the right
#table
syntax->SELECT column_name(s)
FROM table_name1
LEFT JOIN table_name2
ON table_name1.column_name=table_name2.column_name
////example/////
SELECT Persons.LastName, Persons.FirstName, Orders.OrderNo
FROM Persons
LEFT JOIN Orders
ON Persons.P_Id=Orders.P_Id
ORDER BY Persons.LastName
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SELECT
pka,
c1,
pkb,
c2
FROM
A
LEFT JOIN B ON pka = fka;
Code language: SQL (Structured Query Language) (sql)
/* https://www.postgresqltutorial.com/postgresql-tutorial/postgresql-left-join/ */